We do not know how many True Celestials there are, nor how to stop their actions against us. Perhaps there is no way to stop them.
Perhaps when they reach the Upper Realm, these Celestials will realize they can only join the enemies. We can't tell, because none of them returned after their allies fled after attacking the Upper Realm.
Since they can't be destroyed, the Celestials of the universe see the representatives of the True Celestials as their real enemies, the only way to harm the enemy in any way. Whatever the goal of the True Celestials, they seem to need these minions to make their plans for the universe work. Thwarting them is the best way to get revenge."
"So that's it." Minos understood why the seraphim were hated, and why he should be more careful.