It is quite literally an ad-hominem, in that it is aimed at the person, not the argument. The issue isn't that more context is bad (I agree with you, it's useful), it's that as a policy for a discussion board I think allowing this kind of thing is a bad idea. People can be mistaken, or lie, and comments get ugly fast when it's personal. Not to mention the fine line between this and doxxing.

(e.g. here, the OP has claimed that they do not in fact have a vested interest in AI - so was this "context" really a good thing?)