The civil war has been going on for 8 years.
60% of these rebels are actually extremists-https://www.npr.org/sections/thetwo-way/2015/12/20/460463173/60-percent-of-syrian-rebels-share-islamic-state-ideology-think-tank-finds
They believe in Sharia Law, which discriminates against Christians,Women and Gays. Syria doesn't and supports Women's rights
If Assad was so evil, why would he let people return to rebel held areas,like when He liberated Aleppo, why would he let return to Idlib if he was so evil