The idea was that the Democratic voters have never cared all that much about Israel, so if we just let Democrats get right-wing on Israel, there are no consequences for it. But what if Democratic voters cared about changing American policy towards Israel in a more progressive direction? That was a thought experiment, and now it is a reality. What you're seeing now is the fact that a party leadership that has never had to contend with the consequences of these policy stances, is finally getting criticism from it - from within the party, in a meaningful way.