When no one does anything to counter them, or to make it clear they don't speak for the social group, it does actually define said group.
There's a lot more to this phenomenon than you could get into on hacker news, but it goes something like "if you don't agree with everything i say exactly, you're clearly the enemy"
There's a lot more to this phenomenon than you could get into on hacker news, but it goes something like "if you don't agree with everything i say exactly, you're clearly the enemy"