It's part of their land expropriation. They take lands away from their proper owners. Although I only mentioned bloggers, journalists, farmers, and those in rural areas, they also target religious leaders as well—and not even leaders, but participants of non-state-sanctioned religious organizations. That goes against freedom of religion. So they target anyone and anything that in any way expresses their voice or in any way expresses any opinion contrary to that of the communist party of Vietnam. It's not just farmers and bloggers, it's anybody.
On June 4th, 2015. See this statement in context.