Nixon wasn’t all that polarizing along ideological lines. The left always gravitated to the Democratic Party, at least since the days of FDR. The influence of the left has been amplified by the unwarranted expansion of “higher education” (cruel misnomer!) and the ethos of the scribbling classes.
The Left hated Nixon because, unlike McGovern, he did not intend to lose the Vietnam War. Actually, if the Democrats in Congress had honored our pledges to South Vietnam, we would not have lost it, either.
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.