> are all these politicians registered under FARA as registered foreign agents for Israel?

It would be ridiculous to require them to be for simply advocating for a sympathetic position. Doing so would mean the President unilaterally gets to decide all foreign policy, since if a member of Congress takes a position, they're a foreign agent.

> It's become toxic in the Democratic voter base, not the Democratic Party establishment

It's still unclear the degree to which the voters who view it as toxic are politically organized and valuable. The establishment will always lag the ground truth; it would be premature to take a defeatist bent already. All that said, it’s still a foreign policy issue. A small minority will care deeply about it; most people just don’t care relative to pocketbook issues.