Likely because Jowling Kowling Rowling has a history of sending legal threats to people in the UK who speak out about her bigotry, and most celebrities don’t want to get into a lawyer money pissing match with an unhinged ideologue. In the UK the people criticizing her are much more likely to lose a court case if it came to that; in the US, by comparison, it’s very difficult for public figures to have any speech about them removed or punished unless they can prove it is both false and was knowingly said with malice (very hard to prove).
Likely because Jowling Kowling Rowling has a history of sending legal threats to people in the UK who speak out about her bigotry, and most celebrities don’t want to get into a lawyer money pissing match with an unhinged ideologue. In the UK the people criticizing her are much more likely to lose a court case if it came to that; in the US, by comparison, it’s very difficult for public figures to have any speech about them removed or punished unless they can prove it is both false and was knowingly said with malice (very hard to prove).