Is that really what happened though? Is it not the case that the US and Europe have too much appetite for destruction and bending of international rules that has given him the freedom to do exactly the same?
I don't think one moment that the west's aggressive war antics over the last few decades have been reason for him holding back. I think he's not done anything like this simply because he's had no reason to. I distinctly remember Putin losing his **** during the Libya fiasco when the UN allowed western powers to use military force on the promise of targeting only military installations, but then went on to bomb palaces, historic monuments, civilian areas, and sent in undercover agents to bring blood thirsty mobs in to Gaddafi's location where they beat and publicly executed him without trial. There's a video of Putin somewhere promising to never again allow that to happen. Hence Russia's leading stance on keeping the west out of Syria.
Now that the EU is pushing towards his homeland, he's securing his assets without any hesitation simply because the west have given him permission to do by taking their example. The west in this whole situation can't come out in anyother way without being extremely hypocritical.