One can argue over what's driving the conflict today, but how it started back in 2011 is very well documented by every current news source at the time.

It began when Assad's security forces tortured children for spray painting anti government graffiti in Deraa. Protests, in the spirit of the Arab Spring which had spontaneously consumed the region, then followed. Assad met these protests with total violence, including shooting unarmed civilians.

Assad's security service continued to kill and torture unarmed civilians until eventually people started shooting back. Thus began the civil war. Had Assad merely stepped down, as Mubarak did in Egypt, then Syria today would likely be as peaceful as Egypt is.

Here's an excellent documentary, filled with primary sources and not made by some conspiracy nut in their basement, on how the conflict started: https://www.youtube.com/watch?v=njKuK3tw8PQ