Here’s how I see it:
As a poster, @kanicbird, you are free to share – or not share – what you choose to post.
In the IMHO forum, others are free to express their opinions about what you post. This may include an assessment that you are suffering from mental issues, so long as they don’t do it in a rude or dismissive way.
Theirs may or may not be a legitimate concern. You are free to accept their judgments as true or not, and you are free to refute those judgments or not. As you choose. Bear in mind that no one posting has personally assessed you and they are probably not qualified to do so. Nonetheless, we all make judgments about others based on what they say on the board.
We’re not “gate keeping” when we permit others to express their opinions about what someone else has posted. We’d be gate keeping if we didn’t permit it.
The comment that appears to have caused you offense was not directed to you. It was directed to another poster and made in a general way. You chose to take it as referring specifically to you. That’s not an unreasonable interpretation, but it’s equally reasonable to say the comment was meant as a generalization. Also, such a comment may be made out of genuine concern and not meant as a personal attack.
This is only my perspective. I am not a moderator of ATMB. @engineer_comp_geek is, and he always has the final say in this forum. But I hope my comments are helpful to you.