That's kind of a tough call. I can easily understand your point of view, and on the other hand if someone else has been waiting, I can understand his point of view. (geesh, I'm sounding like a politician here, barf barf barf).
Next time maybe ask just to show that YOU are being courteous. And at the same time point out politely they should be docked in position to retrieve their boats. There is also the possibility that when they arrived at the dock, perhaps the boat you were waiting on was waiting on another boat in front of them, and thus was docked where you pulled up, that you may have had no way of knowing.
For the most part, ramp etiquette sucks most of the time. And it's the "offshore" crowd who is always the most polite. Usually it's the fisherman who are the worst.
What sends me into oribit is when someone, on the ramp, decides to either completely load up or offload their boats. Do that in the parking lot.
Remember, basically, most people are totally stupid.