Was it under false pretenses? As far as I'm aware, the Russian speaking minority really didn't support the regime change and there really does seem to be a Nazi problem and the Euromaidan coup really was antirussian (not Russophobic, necessarily, but certainly opposed to Russia) and it really was endorsed by the West. Those are real things that can be negotiated over, Russia isn't just bloodthirsty orcs.

Also, even if I am chopping bodies myself it's still reasonable for me to not want a bigger and meaner body chopper to be friends with the neighbors or to put missile silos in their yard. That's not pearl clutching, that's just rational national interest.