Who was he wrong about?
He claimed various numbers of infiltrators but revealed 159 names specifically.
Of those named, 9 were identified as being actual Communist agents in the Venona files.
Again he was right about the infiltration, but he was wrong about the numbers, and he named people who were not actually guilty of anything.
One example would be State Department employee Esther Less.
She was neither identified by Robert E. Lee as a possibly compromised employee, nor is there any evidence of her in the Venona files, but McCarthy put her name out there as a Communist agent.
How would you feel if you had never done anything wrong and a Senator put your name on a list and called you a traitor?