Because I've seen more than a few unironic nazis hanging around stupidpol. Some of them use the class reductionist mask to hang around that place. So when people like you come wandering in here about this stuff especially on a racially charged topic I can't be certain if you're not one of them.
The comment you made is the most idiotic unhelpful shit ever. It's the same logic whenever someone says not all men. I'm sure women understand that most men are not rapists but guess what that comment is unhelpful and does nothing to further the discussion. It's like a reflexive defensive reaction as opposed to something that will actually get something done.
That kind of comment doesn't come from a place of understanding. So fuck off until you understand that.