Almost exactly as I said. The Russians deported the Tatars. They don't even want the Land, just the Ports.
Ukraine can't negotiate with the Russians. They have to simply say to the Crimean Population. " You decide and we will abide by it "
The word of the Russians is worthless. They signed an Agreement with the Chechyn's after the first " Invasion" there and then they broke that agreement and invaded them again. So Ukraine has to kick them out of the whole country.
Crimea is slightly different just because of the current demographic make up of the current population, so you can't force those people to live through future battles that they themselves night want to settle at the Ballot Box.