I agree with you, generally - so many people need to internalize “It’s okay to not like things, but don’t be a jerk about the things you don’t like.”
With Buckley in particular, much of the criticism is like that, but I think that due to particular things he’s allegedly done - the above sexual assault of a child, for one; the more verifiable (not that I’ve verified them, but I’m sure other people have) claims about him banning people from his own forums for various reasons, like providing (allegedly) constructive criticism of his comics; his generally being rude to many of his fans and critics, etc. - that almost everyone is less likely to defend someone from criticism they’d otherwise speak up about when that person has already earned their ire in some other way. As a result it kinda snowballs and you get pages like that one with almost nobody willing to speak in his defense.
Rat_Bastard