A great moviemaker, ironically his best movie being On the Waterfront, which presents an argument on behalf of snitching. He named names, and what's more, he did it unapologetically, then made considerable money while much of his competition was out of work due to blacklists or jailtime. This didn't sit well with Hollywood, and in fact even when he received a tribute at a recent academy awards celebration, many Hollywood folk, including Ed Harris and Nick Nolte sat on their hands, the clapping being lukewarm at best.
Playwright Arthur Miller, who wrote The Crucible which is about the Salem Witch Trials, but depicting the harsh parallels with the McCarthy era, sent Kazan a play entitled A View from the Bridge (where a man turns in to the INS his illegal alien rival over a lover). Kazan contacted Miller asking, "do you really want me to produce this?" Miller responded, "No, I just wanted you to know what I think of snitches."
They had been good friends, but it was about 20 years before they spoke again. Miller visited Kazan when Kazan was ill, and figured he was getting too old to hold grudges.