It sounds as if “extremism in the defense of liberty” applied at the time because of the willful blindness of more “measured, moderate voices;” or ,not to mix the metaphor, “blind eyes that will not see” in the face of elite propaganda. Almost the template for everything that has gone on since.
On the whole McCarthy’s efforts were probably counter-productive. We would have been better served by someone whose *tone* was moderate, but who was persistent. McCarthy made reckless charges which he could not back up, even if they were true. He tainted the entire enterprise of uncovering traitors in the Government.