I think the left hated Nixon for his anti-communist activities in the 1950’s when he was a Congressman as well. The hard left doesn’t forget its enemies and tries to destroy anyone that understands what they are and how they operate. I think it was Nixon’s knowledge of the far left that led him to be so tragically aggressive in elections, and the experience of having an election stolen from him. That said, he needed to play it straight . . . and shut down their cheating . . . rather than emulate them.
...which is a whole lot more than you ever say for Carter or Wilson.