Idlib Syria is loaded with IS and al Qaeda types (that's a mainstream media source) who flooded Syria and Iraq but who were allowed to leave other areas in Syria taken back by the rightful Syrian government. Assad allowed them safe, free passage to Idlib.
Now those jihadis have a choice: surrender or die. If they surrender, they'll not cause more innocent lives to be lost. They'll be allowed to reconcile. They'll be allowed to return to peaceful existences. If they refuse to surrender, they'll be wiped out right down to the last. They'll be responsible for more innocents being killed in the fighting.
Assad did not start the war. Snipers sent in by outsiders started the violence that escalated into the war. Assad wouldn't give in to the demands of protesters because he believed al Qaeda was right there and would take full advantage of any loosening on Assad's part.
He was right that al Qaeda was there but wrong that he had no choice in how to deal with the naive and ignorant protesters being used by Western spies.
Anyway, he cannot be held responsible for what the West started. He is prepared to liberalize but only with guarantees the West won't undermine Syria again.
It is up to the Syrian people whether Assad will remain their leader. The West has no right to dictate to the Syrian people who they must select from to be their leader after the war is over.