The protests started a loooong time ago, and were peaceful. Right from the beginning, the government would use thugs and snipers to kill protesters. The armed resistance is a relatively recent development, and is formed from army units that defected when the army was being told increasingly to fire on unarmed civilians. This is how dictatorial regimes fall (assuming the resistance carries on to succeed, which is by no means assured).
Remember that this is a regime that razed an entire town to the ground to suppress the last major resistance (Hama, 1982). This is a dictatorship, passed down from father to son, result of a military coup in the 60's, and one of the most brutal, ruthlessly oppressive regimes in the region. You can imagine some people might take issue with that, forcefully.