My name is XXXXX XXXXX I will be assisting you with your legal question.
Unless you have a duty to maintain confidentiality
of an email address, have not otherwise contracted with the person to not give away their email address, and/or are not illegally in possession
of their emails or email addresses, then it is not illegal to post that email address on youtube, given you are not doing it to earn money in some manner.
Further, as long as the email was written to you, then you are free to post this on youtube as well.
Yes, it is possible that you could be sued for some sort of defamation
, but they would need to prove that you are making a false statement about them and that it has injured them monetarily. These are very hard claims to prove, and truth is an absolute defense.
There is no criminal liability here unless you have stolen the email or email addresses (through hacking or other computer fraud).
Please let me know if you have any further questions. Please also kindly consider rating my answer positively so that I am credited by the website for my work on your question. Rating positively does not cause an additional charge and does not prevent us from further discussing your questions.