The Western/UA policy always read to me like the highly evolved philosophical and political understanding you'd see in a second-grade classroom.

It doesn't matter how impractical it might be, or how much long term resentment it stokes: we have to punish ~~Timmy~~ Putin for ~~stealing Steven's toy truck~~ reclaiming the Donbass and Crimea because ~~bullying~~ territorial realignment is Inherently Wrong.

I suspect any non-military attempt to move the line would have been equally rebuffed; any vote to secede would be "rigged", any buyout offer rejected.

The West seems to be profoundly terrified of moving lines on the map in the modern era. Look how long it took to deliver South Sudan, and how Somaliland struggles for legitimacy. Their ability to arbitrate the borders is a symbol of their dominance; once they no longer call the shots, everything is on the table, like fixing an Africa and Middle East full of arbitrary caprice, or finally telling the pipsqueaks in Taipei to stuff it.