One source I found says the Communist Control Act of 1954 did not really outlaw the Communist Party USA. It stated that attempting violent overthrow of the government was illegal, but that wasn’t new law. The act did a lot of ranting, but it didn’t change anything.
As for spies, all nations have 'em, and it was true before Karl Marx was born.
I once read somewhere that McCarthy himself initially saw his role as raising alarm about the high level of communists and sympathizers in influential positions of the US government, and not about accusing specific people, which he felt was the role of the executive branch. His idea was to say “hey, there’s a lot of danger from all these communists and fellow travelers and someone should do something about it”, and this particular campaign was vindicated by history. His problem was that he was challenged to back it up by naming names, and in accepting that challenge he went astray.
For those wishing to emmigrate to the US, membership in the Communist Party or other totalitarian organization is a real issue that can prevent them getting a visa. That’s not quite a direct issue with your statement but it opens a window that is a potential issue for naturalized citizens.
Joining an American based Communist Party within five years of being naturalized is legal grounds for revocation of citizenship and deportation. cite
Most Americans can legally join the Communist party. Some may stop being Americans if they do.
Maybe, but McCarthy waved his list in 1950, and Hiss Chambers hearings in HUAC were in 1948, so it is not like McCarthy was saying anything new. So I’d guess it was about grabbing the spotlight, not about real concerns that the government wasn’t paying attention to the problem.
HUAC has always been an enigma to me. If the HoR is going to have a committee for engaging in activities, ideally, those activities should be PRO-American.