[Trumbo, as editor of the Screen Writer] insisted, perhaps a little disingenuously, that his only standards were literary quality, general relevance, and respect for the [Screen Writers] Guild and its policies and objectives. Richard Macaulay, a screenwriter of conservative leanings and a vigorous anti-Communist, put him to the test with an article, "Who Censors What?" on movie content which was in rebuttal to an earlier piece by Alvah Bessie. As editor, Trumbo rejected Macaulay's article, taking the same shaky position that Herbert Marcuse would two decades later, as he argued, "It is difficult to support your belief in the 'inalienable right' of man's mind to be exposed to any thought whatever, however intolerable that thought might be to 'anyone else.' Frequently such a right encroaches upon the right of others to their lives. It was this 'inalienable right' in Fascist countries which directly resulted in the slaughter of five million Jews.'"
Sounds a lot like the same action/justification as the formal "no platform" policies popular on what's passed for "the left" since the 1970s (once they'd taken full advantage of the '60s Free Speech Movement, etc. to firmly establish their own platform access) and at present by e.g. Antifa groups, doesn't it?
Of course, the right-wing blacklist campaign that hit Trumbo and many of his friends a few years after the incident above was a variation on the same theme -- a variation that seems to be popping up again in tech and other fields, albeit from the putative "left" and without the HUAC-style fireworks (to the extent that there's government influence, it's mostly in the use of general federal equal opportunity regulations as cover for sanctions and dismissals a la James Damore at Google).