Assad/government forces are Alawites and the rebels are mostly Sunni Muslims. Alawites are the minority in Syria but they control the entire country. Sunni's believe they are oppressed and unfairly treated. Assad is killing anyone thats not Alawite to maintain his control so he doesn't really consider these people "his own"
His two day old videos have like 6k views. He really might show up on the O'Reilly Factor one day.
The army isn't exclusively Alawite though. The leadership mainly is. Plenty of foot soldiers/officers are Sunnis and they've allied with Sunni militias in places like Aleppo to patrol/hold territory. There are several units from brigade size to battalion size that are nearly 100% Sunni led.
Before the Russian intervention those units were cut off and surrounded by the rebels for months.
After 2012-13 losses and defections, the army is probably like half Alawite/minorities and other half Sunni.
Also with the regime controlling the urban centers, that's where 70% of the population live and 75% of Syria's population in Sunni.
Damascus and Aleppo are Sunni cities while a place like Latakia is where Assad's sect is really more populated.
This war turned sectarian back in 2012.
