the clash among religions in indonesia

As we know that Indonesia is the one of countries that have a lot of population. Due to large population and a lot of religions that have approved, the clashes among religions seem to be popular now in Indonesia. What are the causes of that? Cited by cross cultural understanding in Indonesia there are two major of causes.
First blasphemy. Blasphemy had occurred since long time ago. Many braws has happened and causes  a lot of victims. For example, we can see how many people have died by big war in poso. And the second is the place of worship. The reality have shown to us, many mosque and church has been collapsed by some ethnic. So what people that we can blame? The first is government and the second is ourselves.