I think that's great news for Labour. I can't really understand JC's reasons or timing tbh.
The pro-JC, Iraq, Gaza are often IMHO also the gender groupies, the cancel culture, the anti-imperialists, no-platforming ones. May they all leave in a huff, plateau at 10-12% at best on a sunny day and squabble with all the other groupuscules.
Free from their Marmite influence, Labour may have a chance to reconnect with the rest of the country. Coalitions can be made with the LibDems, Green or Conservative to keep Farage out.