an unsavory topic: is it illegal in U.S.? My understanding is it is in a grey area, since not real kids but can look enough like them. It's an important topic to mention because I think they were trying to pass an anti-encryption bill recently about CSAM possibly being transmitted over encrypted communications.
I think it's only illegal if it could be mistaken for a real child. Besides the moral problems with hosting their content (federation copies content locally) it puts a giant target on your back for law enforcement.