Calling other people pedophiles without anything backing that would get you a lawsuit even in USA, in every other country in the world much more so.
Its good that you cant just talk whatever shit you like about a person, especially regarding such extreme topics like pedophilia.
If you can verify a fact its not illegal unless in very specific circumstances.
Calling someone a pedophile without any proof and just because you hate them is very obviously not ok and will get you in legal trouble in almost every country in the world.