If Israel loses the Democratic Party, it's over. The debate is already beginning with Bernie and now this.
The state of Israel will never "lose the Democratic Party." Even Bernie says they have a right to exist and defend themselves, so the Hamas sympathizers will not be finding a home in the Democratic Party anytime soon.
However, the Netanyahu administration can and has lost the Democratic Party, which is exactly what Biden's comments are referring to. There is no moral equivalence between blowing up buses and building settlements, but that doesn't change the fact that Netanyahu's leadership only exacerbates the problems.
Israel is moving to the right, so its likely either Netanyahu or worse. No one here is comparing blowing up buses with settlements (settlements are illegal and bad though), but it shouldn't be controversial to rethink our relationship with Israel and other countries in the region.