Whenever pro-democracy activists are asked to explain massive pro-regime demonstrations, their response is uniform: Coercion. Although coercion plays an important role, it is only part of the story.
1- Against the earnest hopes of the overwhelming majority of pro-democracy protesters and activists, political positions in Syria are now drawn along sectarian lines. The regime continues to enjoy the support of the clear majority of minorities (Alawites, Ismailis, Christians and Druze). This core of supporters seems unshakable. Even if the regime continues the killing, and the international community continues to ratchet up pressure, it will not disappear. We can therefore expect to see large pro-regime demonstrations to the very end.
2- The veneer of Arab nationalism and anti-imperialism which this regime trumpets still wins over some Sunnis, especially in Damascus and Aleppo. Some attribute this Sunni support to an elite that has benefitted from the regime, but those elites are insignificant in number. A better theory, in my opinion, is this veneer I describe.
3- Another factor is coercion. If you have noticed, massive pro-regime rallies only occur on working days. This is because a significant proportion of rallies is made up of employees (both public and private organizations) and students. On rally days, everybody gets a half-day off. (A cousin works for a private bank and he gets half the day-off on every rally day.)
Friends have told me how regime forces people to attend rallies. In public organizations, which are the biggest employers in Syria, employees are organized into groups and walked/transported to rallies. In some cases, their IDs are confiscated and returned once they return from the rally. This is done to ensure employees don’t simply sneak home from the rally. Even essential hospital staff attends rallies. A friend of @AnonymousSyria, a popular Syrian tweep, had his son’s operation postponed because hospital staff was at a rally.
The situation in public schools is similar. School staff groups students and escorts them to rallies. Last week in Deir Al-Zor, a 15 year-old boy was shot dead by Shabeeha for refusing to join his classmates in pro-regime rally. (In private schools, the situation does not seem to be as coercive. Another cousin of mine goes to a private in Damascus. Students were given half-day off, but they were free to go where they wanted.)
In my opinion, none of the regime tactics to force people out onto the street are fool proof. (I don’t think it is difficult for people to sneak out of rallies unnoticed.) However, Syria is still a country ruled by fear. In the early days of uprising, enthusiastic media declared that people are no longer afraid. That is not accurate. What has changed is people’s willingness to challenge this fear, but it is still there. I know of pro-democracy persons who joined pro-regime rallies to dispel suspicions that they are anti-regime.
So, yes, the regime has supporters. But many of the people you see in a pro-regime rally are not there completely of their own accord. Pro-regime protesters are ensured their safety, and receive facilitations to protest. Anti-regime protesters are shot at and imprisoned, but they still protest.