Of course, these people will not check themselves, even though JKR gifted them something close to a religion for outsiders. They will just attempt to cancel her.
Not only aren't they checking themselves, they're in the process of deciding that she didn't write her books really, they somehow fell from the sky, or came to their readers via a less "tainted" conduit. Some straight up want Rowling's name taken off the books so they can continue to enjoy them while pretending the author agrees with them.
Call it mental illness or call it a cult - either way, this is clearly not rational thinking or behaviour. Everyone who has enabled those young people in their refusal to come to terms with reality for years, resulting in them reaching this point, should be ashamed of themselves, and I'm very much including the doctors treating them in that judgement. Things should never have been allowed to get this far.
Which is part of the problem women trying to bring attention to this have been facing, that nobody believed it would be allowed to get this far. Nice people just assumed that at some point the government or the doctors or someone would step in and insist that although a person's sense of self is their own and not subject to control by others they do not have the right to impose their views on others. But in fact that has not happened, instead we've had male rapists put into women's prisons and male individuals who believe themselves to be women a few days a week winning women in business awards and anyone who tries to point out that perhaps this isn't a reasonable way for a society to deal with the fact that some people believe themselves not to be the sex they were born as has been shouted down, sacked, and in some cases hauled in for questioning by police.
This is madness and it needs to stop.