And the opinion for which they hate Rowling is not explicitly stated in the Harry Potter books, but can clearly be extrapolated from the fact that Gryffindor girl dorm stairs magically rejects boys.
It has nothing to do with her HP universe, the tweets and comments Themrys and others are (I'm guessing) referring to are about Rowling's RL opinions regarding a certain group.
When it needs to be extrapolated i start to get suspicious it in fact have anything to do with her books at all.
And isnt about Rowlings RL opinion on whatever mess she is poking.