IRAN-Maryam Rajavi;s massage,why must Assad, this murderous dictator remain in power while the Syrian nation wants him out?

why must Assad, this murderous dictator remain in power while the Syrian nation wants him out?

While has half of the Syrian population been driven out of their homeland?
Assad’s continued rule translates into further displacement of the Syrian nation, the influx of millions more refugees to Europe and provides a safe haven for Daesh.
Two parties will be seriously hurt by Bashar Assad’s ouster: One is Daesh which would lose its breeding grounds. The other are the mullahs whose regional front would crumble and disintegrate.
Some people suggest that to eliminate Daesh, we should cooperate with Assad. It is foolhardy to join forces with the murderer of 300,000 Syrians to combat Daesh. For the very existence of Daesh from day one has depended on Bashar Assad and the Iranian regime.
A few days ago, the US Secretary of State said that Bashar Assad and Nouri al-Maliki deliberately released 2,500 extremist prisoners who joined forces to form Daesh.