Early on in his career Blake realized that the church had it all wrong. Since the days of Constantine the church has been the bastion of society, the very same (sort of) society that Jesus deplored. He didn't suck up to the organization; he named them for what they were. They were Rome and the Temple Worship; they were and are about power. But power is not Jesus's program; he preferred Love.
They cast him out; and Blake also doesn't go well in church.