In both cases that Russia annexed, it was after 'referendums'. Both places were filled with populations that identified as Russian. In the donbas case, there was reports of Ukrainian shelling before the wider Russian invasion, but that kind of doesn't matter as there was a civil war going on.

I get really annoyed with the discourse here.

Should Ukrainians have the right to self-determination? Yes. Do I believe anything that comes out of any government's mouthpiece? Not without careful consideration. Does that mean I sometimes fall for propaganda from either side? Yes. Does it mean that I see through a lot? I hope so. Is it frustrating seeing people cheer for dead Russians even though those same people know that these kids will be shot if they don't fight? Very