Defamation is basically lying about someone to damage their reputation. So I don't think that the first amendment gives you the right to lie? Also, doctors and

Defamation is basically lying about someone to damage their reputation. So I don't think that the first amendment gives you the right to lie? Also, doctors and lawyers are subjected to discipline by their respective guild. So even if it's your right to say bullshit, you might lose your job and license. Arguably, there's no to little consequence of being a nobody and lying about something like autism and vaccine. It's probably isn't worth the effort to sue folks. That said, misinformation is clearly harmful and we shouldn't let people lie unchecked.