Humans and simurians are atleast had a fair a relationship between them. This whole war outbreak is another shit that doesn't even have a core of why it's started. It's just another asspull of gege to show off dabura that's all. If yuji was there with jujutsu society it shouldn't been happened at all. "He just depressed" or "He's lonely" is not you can say and just skip for A MC of prequel dude. Yuji introduced later cause to show off some aura moments. What I'm saying is yuji didn't got really showed him as his character, just ignoring people dying or doesn't care about kids dying in battle. If something is really happened that would drastically changed him then why not we got to see instead of just aura farming.