indeed they dont and it has two possibilities.
1. either the issue is much bigger than what we know
2. or is confined only to the ones who make an effort of making an account and spread the hatred.
but, such forums are an indicator of the public feeling too and just the the surveys one can extrapolate it to a bigger group. you cant just ignore it.
I remember when the web was in its infancy and we only had the dial ups to connect tot he web back in the late 90s, right after the nuclear tests, Indians went nuclear on the chat rooms too (I agree that small proportion is not the true representation of the whole nation) but that continues till today, where the amount of venom, hatred and mockery is open to see where the expression is not moderated. I am talking about the stories of terrorism and the the victims in Pakistan and the kind of comments that are posted.