Rev. Wright vs. Rev. Right

The argument was inevitable: If Barack Obama is being held responsible for the views of his preacher, shouldn’t Republicans be held responsible for the views of all of those right wing white preachers who support them and who can sound (especially to secularists) just as whacky? See E. J. Dionne Jr. – Fair Play for False Prophets – washingtonpost.com. Is there a moral equivalence here? How would you answer this argument, or can it be answered?