Well, yes -- but if we focus on the big picture (as opposed to this particular issue), the Koran defines how you're supposed to do everything. It's a huge set of regulations, and not all of them are straightforward. The purpose of an Imam is to answer questions in the "right way," because wrong answers get you sent to hell.
In that sense, it's not much different from our having to rely on a tax attorney to keep us out of trouble.