The government doesn't have the right to tax churches, so long as they are churches. When they become arms of a political candidate then they are no longer a church.
I disagree that a pastor/priest cannot bring pressure on politicians who do not practice the tennents of their faith.
I don't believe the article says what denomination this church is a part of, I suspect it's a generic 'Christian' church, but I doubt that either Obama or Clinton are a part of it. He isn't criticizing their faith, but their politics. He's become a political organizer, not a preacher.
Maybe he is if he's discussing subjects like abortion, which would be religious and not political. It could possibly be both, but it's religious first and foremost. It's one of the Ten Commandments "Thou shalt not kill".
Another Commandment "Thou shalt have no other God before me" would be considered Hate Speech if a pastor criticized Islam as a false religion. If some folks had their way, a pastor could be silenced for preaching the Bible in this case also.