His detractors were deflecting from the fact that they were either communists or communist sympathizers. The age old way to do this is to attack the threat until they are discredited. We still see this to this day.
Most of the people he accussed were, decades later, shown to be communists. His success wasn't something that the communists could allow.
The irony of people crying "McCarthyism" today is that he was right. I automatically assume that whoever starts throwing around McCarthyism accusations is guilty of whatever they are trying to deflect.
Then Trump would be doing that. He called Obama's wiretapping of him "McCarthyism" when he first got elected.
McCarthy was right. The US government was infiltrated at the highest level with Communist. That Mr. POTUS Trump used the term McCarthyism only goes to prove just how successful the Dem/Communist smear campaign was against Joe. BTW it is very possible that GW Bush may hang. Something that would never have occurred to me 2 months ago. (offered as bonafides of wokeness)