Because it is widely perceived as socially indefensible and because of YC's support for women in particular.
Perhaps it is an unfair to apply these generalizations to you, however I seriously doubt you (or any public figure) would depart from them.
Nonetheless, the point was more general: Obviously you form opinions of people without knowing them personally.
> In this particular case I commented because I have direct experience with some of the people being discussed and am familiar with the ways in which the popular group-think diverges from reality for this group.
I pointed out that your experience may not be informative because of the particular power relations of your interactions. I think that is a fair observation.
This group is ill-informed, has poor reasoning skills and poor judgement. That doesn't have any bearing on the question of whether successful people are more likely to be sociopaths.
> I know it's pointless to argue with people who already know the answer
You could apply the statement equally well to yourself.