What? Yes, lots of people are protesting and have been for over a year. I don't know precisely how many of them personally call their reps, I know I have been, but I think the massive, widespread protests combined with polling Democrat voters about their views on the matter makes the message pretty clear. Politicians have had plenty of time to respond.
The counter-argument to your point is that now is the best time, as voters have the leverage to elect democrats or not. In theory, Dem leadership wants to be elected and requires votes to achieve that goal. Biden met with progressive activists shortly after taking office and promptly told them to fuck off as, since he was already president, they no longer had anything to offer him.
That said, I hear your point and am torn about how I will ultimately vote. I don't live in one of the nine (arguably three) magic states where my vote will actually count, though, so it's a bit of a moot point.
Obviously less, to the extent that anyone can predict geopolitical events that far in the future. I think the only counter-argument is the idea that an Israel that isn't receiving massive amounts of US aid will be invaded, but I don't find that argument convincing. It's an open secret that Israel has nuclear weapons, and even if the US stops arming Israel tomorrow I don't think Iran or their proxies are dumb enough to think that the US won't come rushing right back in if Israel is invaded.
The protestors want an end to the US facilitating genocide. Most Democrats want fewer, if any, aid to Israel, yet Democrat leadership refuses to budge.
You blame voters for "being willing to let Trump win". Why not blame leadership for hurting their own chances at election by going against their own base?
All of them, frankly. It's against US law to provide weapons to a nation that is using said weapons to commit human rights violations. My expectation is that the US follows its own laws.
Because everyone knows that Trump is not going to move on this issue, or really do anything good at all. Dems are supposed to be better than Trump, or at least they certainly insist that they are. People holding Kamala to a higher standard are taking the Dems at their word.