People will do that. It's happened to me a couple of times. Nothing you can do about it, though, and you're not allowed to complain about it. Just take your lumps in silence.
I see it as not so much “take your lumps”, but more like “Meh, haters gonna hate - just ignore them.” Not a perfect solution, sure, but if you wanna participate on a anonymous/pseudonymous forum, that’s kinda inevitable. What’s the alternative?