Did you read the Ukraine live thread when the Euro Maidan “protests” were happening? Caww provided yeoman reporting along with lots of photos. I read every inch of that long thread and it was a huge eye opener. Caww - if you have a link to that thread, would you mind posting it?
The situation in Ukraine as “evil Russkis/innocent oppressed Ukrainians” was propaganda. And that includes Crimea. Crimea has traditionally, historically, belonged to Russia.
I couldn’t find the archives on that...sorry.
Moreover they have that big naval base in Sevastopol. But I thought Mr. Putin did some things to sweeten the russo ethnic mix to make it look better when they moved.
Anyway, that was the price we paid for putting zero in there. There was no one to stop him and like you say, they have the historical claim to it. I believe they took it from the murky Turks.