When you phrase your opinion as "I don't like this so you shouldn't get to enjoy it or see it" that's a problem. In fact I think that's THE problem that's being called out here. Do you go into a restaurant and specifically call the cook out of the kitchen so you can announce to everyone that you think the food is bad? Because that's what it seems like.
They are talking about "I don't like this artist, but to each their own" comments. They aren't even talking about valid criticism of the author (I see some actual valid criticism here that I'm fine with).
I am not even a pizza cake fan. I have no skin in this race. If I never saw another one of her comics again it would not matter to me at all.