This is of course profound question with no clear answer. There are arguments on both sides of the issue.
Some have professed that women are under-represented in the legal system (e.g. not as many women judges and lawyers), and that as a result the system is slanted toward the male view of social issues. For example, some have argued that the courts reject the "battered women's syndrome" (in which a woman claims that she killed her husband to protect herself from ongoing abuse), and yet the courts accept the "heat of passion" defense to some crimes (in which males are more likely to use this defense). In a case from my jurisdiction, a young woman sued an institution for fostering an environment in which she was raped, and the court held that the woman was negligent as a matter of law by becoming intoxicated; that decision was criticized as being male-centric.
On the other hand, the judiciary is theoretically neutral, and offers a forum for women to achieve justice that they may not be able to achieve in society and through legislation. Some may contend that Roe v. Wade, for example, was a major victory for women, that they could not achieve in the Legislature (in the Texas legislature anyway).
Further, the courts enforce several acts of legislation that ensure or promote women's rights. For example, the laws that protect women from discrimination in the workplace are enforced by courts.
Some even contend that the courts are overly-protective of women. For example, many men contend that the family courts favor the women. For example, they claim that the courts grant custody to the mothers more than is justified. Further, many men claim that when a court is faced with an allegation of domestic violence against a woman, that the courts tend to err on the side of the woman, and to enter the protective order, even where the evidence of abuse is weak or non-existent.
It is important to distinguish between those instances where the court is simply enforcing legislation (i.e. equity and justice created by legislation), and where the court is making law (e.g. common law). The judiciary has far less ability to affect social justice when enforcing legislation (other than to honestly enforce the law). When it comes to making law, the courts have more flexibility to shape the law.
As can be seen from these few examples, this is a multi-faceted issue with no clear resolution. On the whole, viewing society in the scope of the last 100+ years, the judiciary certainly has generally promoted women's rights, but of course perhaps more can be done.
It is difficult to provide more guidance on such a broad question. If this has been helpful, please click "accept" so that I may receive credit for this response. Thanks.
Lawyer
20 years of experience in general law practice.
To be frank, it is not surprising that you are confused. This is a confusing topic, and there is not really a good answer to it.
Much of the problem here arises from these terms, which are subject to great interpretation. I assume that the "legal system" in its broadest sense, including legislation and the judiciary. (I will assume that we are not talking about a religious legal system, but that may be called a legal system also.) The term "social justice" is likewise an amorphous term. It would generally seem to refer to justice in every aspect of society, and not merely in the administration of law. There are, however, several variants of "social justice." For example, "justice" is a very subjective term. It seems to generally encompass freedom of speech and thought, freedom to choose one's occupation etc. To some it is the redistribution of wealth. Finally, the terms "human rights," "equity" and "restorative justice" are elusive. These seem to generally refer to some notion of fairness, and basic human rights, which is largely similar to the rights sought in "social justice" (and may also include e.g. a right to food, right to work, right to education). "Restorative justice" is a different concept, which recognizes victim's rights, promotes restitution, and a community-based approach to achieve justice in a peaceful manner.
Hence, the question posed is immensely complex, and could easily fill a whole book. One approach would be to look at both sides of the issue.
Certainly in many respects the legal system has enhanced all of these issues (e.g. human rights, equity, justice). Our state and local governments are largely focused on preserving human rights. For example, most of our criminal laws are designed to protect many of our basic human rights; i.e. to be free from harm from others. Our laws against murder, rape, assault, drunk drivers etc. all aim to protect our basic human right to safety and to the integrity of our body. One aim of these laws is to deter these violations of our rights. Further, we have government-based programs such as Medicaid to provide a base level of health care to certiain people, as well as food-stamps for food and college loans to assist needy people with education. We have passed laws specifically aimed at equality and fairness, such as (in the USA) laws that prevent employers and restaurants and motels from discriminating against people on the basis of race, age, gender etc. We also have voting rights acts which seek to ensure access to the right to vote. We provide free public schools generally through the 12th grade.
Many of these laws have helped to advance women. The laws ensuring women equal opportunity in the workplace, and the right to vote, are clear examples of the "legal system" advancing social justice for women. Further, to the extent that women were historically denied jobs and higher education, the job and education programs (focused on the needy or under-represented) benefitted women (and brought about justice). Laws to protect women brought about social justice for women, by protecting their fundamental right to safety and the security of their body. For example, many laws give women the ability to obtain a restraining order against an abusive spouse. To the extent that women are victimized (e.g. rape), then many states have enacted laws to protect "victims rights," allowing them to provide the court with a "victim impact statement," and this is a form of restorative justice. And very broadly speaking, our legal process is generally gender-blind; a female plaintiff has the same rights as a male-plaintiff; and a female defendant is subject to the same laws as a male defendant; hence, these laws and our system as a whole promote equality for women. (If one looks at some religious "legal systems," then it is clear that those are not always gender-neutral.) One can therefore look at many legal doctrines and systems that promote justice (and "social justice") for women.
One could also argue that the "legal system" has hindered social justice for women, but these arguments take more creativity. If, for example, the public develops a general sense that women can advance in business and society only if they are given legal advantages (e.g. affirmative action, or incentives for "minority"-owned businesses), then society (especially males) may develop a resentment toward women, and may conclude that women are inferior, and they may discriminate against women in other ways. Also, if some egalitarian laws are over-enforced, society can backlash. For example, many people believe that laws againt a hostile work environment have gone too far; for example, some males are fearful of making an "off color" joke at the workplace; this can theoretically create resentment and ultimately discrimination against women. Also, much of our legal system is not truly driven by fairness, but is driven by political and economic incentives. Our politicians (and legislatures) may enact laws which result in (perhaps unintentionally) unfairness toward women, because it will promote the politicians (by e.g. an expetation of ongoing campaign contributions). This issue can be seen with, e.g., the abortion issue. The recent partial-birth abortion law (which was upheld by the Supreme Court), for example, does not have an exception for the mother's health (i.e. allowing the PBA when needed for the mother's health). This law was arguably driven by political pressures, but in some people's view of "human rights," it risks infringing on the woman's rights. (Of course, this hypothetical also raises the problem of the subjectivity of this whole discussion. Whether the mother or the unborn child has the greater "right" is in the eye of the beholder.) And certainly if the public in general comes to rely on the legal system for justice, then it may do less in the private sector (e.g. community involvement) to promote human rights issues (e.g. not reaching out to disadvantaged people, engaging in legal pollution).
I hope this has helped you to think about this a little. The question is very broad, and is difficult to answer. If this has helped you, then please click "accept" so that I may receive credit for this response.