McCarthy is a pretty unique figure in US history in that he was infamous for propagating the second "red scare" in the US. That's not to discredit these reports by any means, but it's not like he was do-gooder either. He was a vicious politician that didn't hesitate to accuse his enemies of being communist, which sometimes resulted in arrest and prosecution. [0]"McCarthyist" anti-communist (i.e. opposition political organization) laws were passed that were later struck down by the Supreme Court.
His ability to accumulate power this way made him a major political target, which isn't quite the same as someone just trying to reel in the 3 letter agencies.
0: https://en.wikipedia.org/wiki/McCarthyism