Russia should not waste the valuable blood of her soldiers hunting the neo-Nazis. Russia should do what the Americans are doing around the world, and use drones to hunt the terrorists in Ukraine. The illegal Ukrainian government is harboring terrorists and so itself is a legitimate target for Russia.
This would be a splendid idea! However, drones have drawbacks: they are expensive and they kill innocent people. Russians will not want to do that exactly because they are not fascists. Putin does not want bloodletting. He truly cares about lives of both Russians and Ukrainians.