Yeah that’s fucking stupid. Most fans of a franchise care about the franchise, and especially with one this old, they treat it as a part of their identity and deeply like it.
Stupid statements like this will only alienate them and make them give Rowling money anyways. Instead, you could easily get some people to avoid paying Rowling for stuff (e.g. buy third-party Merch or second-hand stuff) and reclaim it (e.g. supporting the actors’ views instead).