[pcthrowaway]

Wars are bad, but sometimes the only way to end an unjust status quo. Is that a defense of war? Up to everyone to decide.

The American civil war occurred, in part, because Lincoln decided to end the institution of slavery. I know this is an oversimplification and justifies the means with the end, but I think if "bad"-ness of the civil war is compared to the "bad"-ness of an eternity of black people being enslavement in the U.S., I'd argue the war was significantly less "bad".

I think your other point about Hamas's supposed desire to genocide Jews lacks nuance, and your resignation to a world of ethno-nationalist states is a just-so story bordering on nihilism, but I suspect addressing those enters territory of tightly-held opinion, so I will just leave it at that.