In particular, it's probably no coincidence that Hollywood adopted its blacklisting policy immediately after the HUAC started going after major Hollywood figure

In particular, it's probably no coincidence that Hollywood adopted its blacklisting policy immediately after the HUAC started going after major Hollywood figures. Congress had sent a clear message that the First Amendment did not apply to anyone who was perceived to be friends with a communist, and Hollywood responded with what was probably originally an act of self-preservation. That kind of authoritarian curtailment of freedom of expression and freedom of association is precisely why I railed against the idea of drawing any lines up above. When we start talking about drawing lines we're implicitly talking about criminalizing a certain kind of behavior. It's the first well-intentioned paving stone in a road that leads directly to tyrannies such as McCarthyism.