You cannot compare US involvement in Afghanistan and Iraq to the one in Syria. Russia and Syria have been tight since the 70s when Assad Senior was in power, Russia kinda owes them a duty of care and cannot just watch as the US turns it into another Iraq.
I would have liked this twice. All dominant empires behave like US. Most in history were worse. You have to keep others down and exploit them if you want to stay in power. That applies to all politics even in kenya. We have our body count since independence(citizens and politicians). The world is a Fuckin brutal place.