Based on what evidence? McCarthy also went after George Marshall. Clearly he was prone to overreach.
We would be beating a dead horse, many posts already on this thread why McCarthy would have been justified about Oppenheimer. As to Marshall, haven’t a clue.
The very fact that McCarthy is the communist left’s favorite punching bag, and in view of what we have foisted upon on us by the Clinton and Obama years, is reason enough for me to come down on his side...even if he may have overdone it a bit here and there. Would to God we had a senator like him around today!