They're fighting for their own existence. Russia has killed, enslaved, and/or tortured most of the citizens of the regions it's already captured, and replaced them with ethnic Russians.
I think "killed, enslaved, and/or tortured most of the citizens of the regions it's already captured" is an exaggeration. That is not to deny Russian war crimes, which are clearly large-scale and horrendous. But I don't think the majority of people in those regions have been killed or enslaved.
I'm a big supporter of Ukraine and have donated to the war effort and hosted Ukrainian refugees.
I'm a big supporter of Ukraine and have donated to the war effort and hosted Ukrainian refugees.