Russian troops could simply be operating under the premise that none of their actions would be necessary if the West hadn't meddled and created the Ukrainian crisis in the first place. It's that simple.
Ukraians are sick of being taken advantage of by Kremlin so naturally they opened towards the west. It’s their choice as a sovereign nation. If they consider they get a better deal with the west then what do you expect the west to do, reject them for fear of Putin?
I wasn't trying to explain the actual political situation. I don't know what "deal" they took exactly. It's just really easy for any side, including the actual Russian individual taking orders, to delude themselves about the enemy and who is really to blame. For example, it doesn't take much for an American soldier to waltz into the Middle East and purport to be focused on building schools, and they even demand respect from much of the populace while doing it.
That being said, the underlying viewpoint behind the convenient justification is not that controversial on its own because the West was trying to win over Ukraine through various means. This is seen as something akin to nation-building even by some American academics.