He’s been fed up with the PC crap for a couple of decades; comedians aren’t permitted to be funny anymore.
I’ve always liked Seinfeld’s comedy, but he is all over-the-map schizo about leftist culture. One day he’s complaining about wokeness. The next day he’s saying that wokeness isn’t a real problem. The day after that he’s defending Israel and knocking colleges for coddling anti-Semitic demonstrators. The next day he’s saying that college campuses are fine.
To some extent, he’s kind of a nicer, milder version of Bill Maher. He’s a man of the left, but occasionally he gets so disgusted with the left’s antics that he blurts out the truth.