Why don't people "boo" during sermons when a preacher says things that are way out of line?

every other speaker, comedian politician etc. is subject to negative reaction from the audience when they try to say things that are out of line, or contrary to conventional wisdom. Why should preachers be immune to these checks and balances, and be free to harangue and brainwash the simple minded believers that accept everything he says as profound truth, and vote, act, and emote, at the whms of preachers. The rev. Wright's recent statements are just one example.no one in the congregation dared react negatively.Why is this?