When the old Nazis of the Adenauer govt started supporting Israel (and the genocide convention), they did that not out of genuine guilt, but because the US said so, and so they could use it as in their anti-communist propaganda (“See we are morally superior and you’re doing all these terrible things <insert atrocity propaganda here> over there in the east. Maybe we need to do something about that!”).
Perhaps later generations actually started to feel ashamed for their opas, but they too used this as justification. “Oh we’re sooo repentant, that makes us so much better than all you unrepentant sinners and btw it means we definitely need to bomb Belgrade.”
And now they’re using it to pummel Palestinians (and also all Muslims, both in Germany and elsewhere), because those have not accepted they’re also filthy sinners/antisemites, and the Germans can put all their opas’ sins on that scapegoat and be cleansed. And who better to put this on and punish, than the people they already hate, and whose resources they want to steal.
tl;dr It was originally fake abuser logic, and now se Germans have it internalized, because it makes them feel superior and can be used as a weapon.
They don’t need get rid of their guilt, they can just stop abusing it for their selfish desires.