The term "ethics," surprisingly, has little to do with legal matters (except in cases of professional license disciplinary matters by a state agency against a licensed professional).
Things are either lawful or unlawful -- ethical considerations have no relevance, and the court's jurisdiction does not consider the morality or ethics of individual conduct.
That said, the issue here concerns copyright infringement
-- which is a pure legal matter.
Every document is the intellectual property of its author (absent license to another, or work made for hire under an employment relationship or special commission) -- and a copyright
arises "in original works of authorship fixed in any tangible medium of expression." 17 U.S.C. 102(a).
A set of articles or bylaws found on the internet, may be abandoned into the public domain by its author -- by virtue of the author failing to make any attempt to protect the work (e.g., no copyright notice, and no actions against infringing parties). The documents may also be so filled with "boilerplate" language that there is nothing particularly original about the work -- other than reordering or rearrangment, which is not considered to be sufficiently "creative" to sustain a copyright under law. See, e.g., MATTHEW BENDER & CO. v. WEST PUBLISHING CO., 158 F.3d 674 (2nd Cir. 1998) ("...choices on selection and arrangement can reasonably be viewed as obvious, typical, and lacking even minimal creativity...are not copyrightable.")
The point here is that it's largely a judgment call. If every contract were susceptible to copyright protection, it would be practically impossible to contract for anything without paying someone else for the privilege. Consequently, only in cases where a legal instrument is so novel that it is overwhelmingly a creative product, can it be said to be protected by copyright. Otherwise, anyone can use the document for whatever purpose they see fit -- and, their derivation is almost certainly also "not copyrightable," or subject to protection.
BotXXXXX XXXXXne, if you are sued for copyright infringement, for the use of a boilerplate set of articles and/or bylaws, then you will probably be the first person ever to be sued for doing so.
Hope this helps.