@DSeid suggests that Haley Stevens endorsed MAGA Rogers with his Nazi staffers based on principles of opposing antisemitism and supporting Israel (or something like that), and described the positions of people he knows as justification:
I don’t know how widespread this is, but this is some kind of strange variation of White fragility. It’s not remotely rational to shift from supporting Democrats to MAGA Republicans with Nazi staffers based on a third party ad from a trolling grifter. There’s some weird pathology at work here.
Whether or not some Jewish Democratic voters actually feel this way (and any that do are not remotely acting rationally), I still don’t think it’s at all reasonable to believe Stevens did this on principle rather than over sour grapes, grift, or some other illegitimate reasoning.