This looks like an interesting page... beware I have not read it fully, just now found it..
http://www.caic.org.au/zabusive.htm
From what I can tell, the motives behind abuse in the church usually head in a few distinct directions:
Sex, money, power over followers, claims of being 'the prophet' etc.
I read somewhere a while back about a priest who was telling kids that he was the second coming of Christ, then he would sexually abuse them. boys if I remember correctly. It's one of thsoe well known cases you may have heard of it... but little kids, even adults, new christians, when they hear this from a high up memeber of the church they attend, what are they suppose to think? These guys wear the robes, have the degrees and the positions of power, the people look behind and say 'how can all these people be mislead it just cannot be..,'
it's a difficult situation at best.
The bible does say beware of false teachers, it's in there for a reason, people really do need to heed it. they see signs and wonders, they go running, but the bible says distinctly, beware of that.
Maybe it's God determining those who desire signs and wonders above Him alone, and obedience to His word. I have considered that often. The signs and wonders are out there, I would be hard pressed to tell they are all from God, quite the opposite... so in there is the devil at work too...
Kind of dampens the credibilty on things like theological doctorates for sure... a man should be led of God, not the ideas of men (or himself). Anyone can get a college degree if they have the money and time.