It may not have been intentional by Clooney, but this movie came out around the time that conservative writers Ann Coulter and M. Stanton Evans published books attempting to rehabilitate McCarthy. In that context, the movie's a useful reminder of why McCarthy has such a negative reputation.
The Roosevelt-Truman administrations did have Communist sympathizers in them. However, that doesn't change the fact that few of McCarthy's claims were substantiated in the hearings. So more like "strawman's political maneuvering happened to align with reality." In fact, McCarthy admitted that the "list" he waved around at one speech was a mundane to-do chores list.
The point is that only one of the people McCarthy accused, Mary Jane Keeney, was actually anything close to guilty. Even then, McCarthy accused her of being a Communist party member, which distracted from the fact that she was actually a GRU spy and suggests that any attempts to claim that McCarthy "was right" suffer from the Texas Sharpshooter Fallacy: a man shoots wildly into the side of a barn, draws a target around the bulletholes, and then says "look at my deadly aim!"
In-Universe, Bill Paley notes that even Murrow was worried about looking like a Communist sympathizer by remaining silent about Alger Hiss. Murrow has no response for this. Instead, his defense is that at some point, a line has to be drawn.