Assad was elected after he rigged the presidential polls. He has used barrel bombs and artillery against the civilian targets, and has rejected all the offers for compromise. He is actually responsible for the rise of the ISIS in Syria.
The most barbaric of the atrocities in Syria against the civilians were committed by the same rebels which you are supporting. Have you seen the video of the beheading of the 12-year old Palestinian boy by the rebels? Or have you read the story of a 1-year old infant blown to pieces using an explosive device, just because his father refused to join the rebels?