I honestly don't want to engage in the debate whether commies were a threat. The ones in Russia with the bombs, most likely. The idiots running around in the US? Very debatable.
I know the hearing between Welch and McCarthy rather well (I dare say most likely better than most non-US people). Its importance is less in what transpired, what mattered is what effect it had. It was the end of the witch hunts. Because that's what the whole zeal to find commies turned into. What went down in the US during those years around whether or not someone was a commie was not far from what happened in Russia with whether or not someone was anti-commie. The main difference being mostly that the outcome was less lethal in the US. The process itself, though, was the same mix of hysteria, opportunism and people who used it to get rid of opponents, as well as an excuse to do "whatever is necessary" and "end justifying any means".
I cannot help but find the same attitude now towards the proverbial four horsemen of the infocalypse. Is there a threat? Yes. Is it as big as we're led to believe? Hell no. But it is a very neat vehicle to get whatever you want because nobody may oppose it without provoking the question "or are you a commie/terrorist/pedo/whatever?"
Black and white. You're on one side or the other. The idea that BOTH sides could be wrong is not even offered as an option.