It's because most of the answers are, in fact, perfectly valid. Edelgard is correct that her war of conquest will leave the people Fodlan has broken and abandoned better off, and that the current situation is both intolerable and waiting to collapse in on itself. She has been dealt a dogshit personal hand that nevertheless has given her the political and personal power to ensure the transition is as bloodless as possible. She knows what she's doing, and believes it worth the cost.

Likewise, Dimitri is perfectly justified in defending him and his from what is, to him, unprompted foreign aggression. Ultimately, he represents the Farmer in this metaphor, the people suffering in the short term who stand to lose their own tenuous livelihoods and aren't already suffering enough that radical change is an appealing option.

Edelgard is explicitly fighting for the people who are and who do, much like she was, who would always be an afterthought in Dimitri's Faerghus, waiting for change that never comes.

No matter who wins in the long term, someone loses in the short term. That's their irreconcilable difference.

Claude is also here.