The First Amendment protects you against government laws an regulations that inhibit, among other things, your ability to peacefully assemble.

The comment looks like they were blacklisted from the entertainment industry presumably by the industry itself, not the government. No government action, no violation of the 1st Amendment.

Anarchists were also not allowed to enter the US and could be deported for being Anarchists, this has not been uncommon in American history, or Western history for that matter.