I saw the 'undecided' crowd (which was a concept that came after criticizing Biden and discouraging voters for months) credited themselves with him making that decision, though I doubt it was the only influence. It's been kind of apparent that political opponents have been using that as an issue against Biden and it is pretty unpopular, not to mention generally wrong, so of course he should change policy. I think they can figure that out themselves too.
Well, if you have figured out a way to stop AIPAC from influencing US politics, great! It's only been about 80 years of sending them billions of dollars in weapons and arms each year. The idea that Americans are going to send their own politicians to international criminal court in the EU is pretty far-fetched. I'd start with Bush, Rice and Cheney personally.