You seem to think that letting the more genocidal republicans win would encourage the democrats to be less genocidal, which is bizarre.

They are the same. They both support Israel undyingly, Biden is even sending in the troops.

They move right when they lose to compete with the republicans because the republicans win with a right wing strategy.

They move right because that's what their donors want.

If the democrats won all the time, the republicans would have to move left just to regain power, and the Overton window would move left.

No, they wouldn't. Fascism is Capitalism in decay, both parties are always moving rightward.

Not voting for the democrats in order to move them left is insanity. They will respond by copying the more successful electoral strategy.

If the Democrats don't want to regain left votes then they are too far gone and we need a revolution.