Within the context of condemning political violence following the murder of Charlie Kirk, she quoted on X a line from Mein Kampf where Hitler talked about how he utilised political violence for his own gain. This was a clear statement in how allowing for political violence against one's rivals can lead to that in power manipulating things in order to harm others.
Unfortunately, articles are springing up across the internet shaming JKR for quoting or referring to this text at all, with many condemning her for 'nazi' views and accusing her of being far right.
(Personally I love JK, and it is such a shame that every single thing she says is twisted to mean the opposite of what she's actually saying!)