This is like arguing that confederate generals actions weren't treasonous because they weren't charged and look there are military bases named after them!

Harry S Truman wrote during his presidency: "We want no Gestapo or secret police. FBI is tending in that direction. They are dabbling in sex-life scandals and plain blackmail

He was a villain by any reasonable accounting whose exploits are at this point well known and his moral deviance, bigotry, hatefulness, contempt not so much merely for the letter of the law as for its spirit and purpose. A contempt for justice as it might be understood by anyone other than a straight, white, conservative, republican, man that ultimately overshadows his accomplishments.