It doesn't have anything to do with being a "lib degenerate", its about how much AIPAC campaign money he receives, which could be cut off, and worse, given to a challenger.
This won't work on Feinstein because she gets no AIPAC money, her Jewish campaign money comes from J Street, who support the Iran agreement
From time to time, ChiFi has surprisingly stood up and done the right thing. She respects Schumer a lot. Say what you like, I think it's worth a shot leaning on her over this.