Why do different denominational pastors claim they're divinely guided?

Because there is big differences in the denominations on different things, yet they ALL claim they've been called into ministry, so wouldn't the same God all guide them the same way? Some say speaking in tongues is correct, so don't for example, yet the pastors all claim to pray to the same guy. Don't use the argument that some are fakers, because you would have sworn Ted Haggard was called by God before he did it with a gay prostitute, he obviously wasn't a faker more than the pastor at your church is.