Why legitimate government of the country should back down, facing peaceful or not peaceful protests, supported by foreign powers? Why civil war is Russia's fault any more than it is fault of Western countries, Turkey and Saudi Arabia who are trying to overthrow the leader which they don't like, supporting the opposition and terrorists diplomatically and financially?.
Well 'legitimate' is questionable as Syria has been a family run affair for generations, but that's reality, I can accept as it is real politik. I'm simply pointing out the hypocrisy of the situation as this is clearly a case of a Russian/Western proxy war yet, a commentary here for certain posters on the 'left' omits Russian involvement and or downplays it.
I believe, and this is only a belief of course, that Assad would have left peacefully had it not been for the fact Russia & China backstopped his survival and guaranteed UNSC would not get involved, allowing him to 'crackdown' on the protests and starting a civil war. Russia did so because they saw it as part of a large geopolitical struggle that stretched from the caucuses to the ME. Russia of course had only recently (at the time of the Syrian protests) invaded and humbled the former Soviet republic of Georgia, which it saw as slipping into the western sphere.
Let's also remember, this was part of a wave of protests in the region, not as an armed insurrection. But people can be forgiven for forgetting because Russia has had their hands in this thing for 3 years. It's been that long.