A free society does not use the government to punish "thought criminals." This does not, however, mean that free people had no acceptable way to express their disapproval for Stalin's apologists. One route, of course, was to take up the pen in defense of the victims of Stalinism. A second - and equally legitimate - course was to exercise one's freedom to not associate with Communists. Not to befriend them, buy their magazines, or hire them - and to urge other people to do the same. In short, to blacklist them. Far from being a violation of anyone's freedom, the blacklist is merely an exercise of the freedom of association, just as a peaceful strike is an exercise of the freedom of association.
It has of course been a long-standing argument of Marxists that both prison and the blacklist - both the threat of violence and the refusal to trade - constitute coercion. Only their ideology prevents people from seeing this. Mocking the bourgeois view of freedom, Marx writes that, "Liberty is, therefore, the right to do everything which does not harm others... It is a question of the liberty of man regarded as an isolated monad, withdrawn into himself." Elaborating: "The right of property, is, therefore, the right to enjoy one's fortunes and dispose of it as he will; without regard for other men and independently of society... It leads every man to see in other men, not the realization, but rather the limitation of his own liberty." (On the Jewish Question)
Yet turn the issue however you wish, it is impossible to maintain this position consistently. If a woman refuses to marry a horribly deformed man, we may sympathize with his plight, but he can hardly claim that she has violated his rights. Or as I put it in my analysis of Marx's critique of "bourgeois freedom":
[I]t is difficult to understand how Marx's concept of freedom is anything more than a defense of tyranny and oppression. No dissident or non-conformist can see society as the "realization of his own liberty." And what can the attack on "the right to do everything which does not harm others" amount to in practice, except a justification for coercing people who are not harming others? The problem with "broad" notions of freedom is that they necessarily wind up condoning the violation of "narrow" notions of freedom. Under "bourgeois" notions of religious liberty, people may practice any religion they wish ("a private whim or caprice" as Marx calls it); how could this liberty be broadened, without sanctioning the persecution of some religious views?
The blacklisting of pro-Communist screenwriters, actors, and so on was particularly appropriate as an act of cultural self-defense. I daresay that if Hollywood had been largely pro-Nazi, World War II would have sparked a massive wave of firing of not only American Nazi Party members, but anyone vaguely sympathetic to their views. And what would have been wrong with that?
What is most absent from recent reflection on the Red Scare of the 1950's is any sense of the moral depravity of the victims. Yes, Communists have the right to defend the extermination of the kulaks, just as Nazis have the right to alternately defend and deny the Holocaust. This does not turn them into heroes. True, Communists posed little threat to national security, just as Nazis are unlikely to seize power anytime soon. This does not mean that someone is paranoid if they ostracize them - personally, socially, and/or economically - and encourage others to do the same. Everyone is entitled to your tolerance, but not everyone is entitled to your respect - or your business.