I hate retractable leashes too. Used properly, probably they are ok, but I'd venture to say MOST people using them do not seem to realize the length can be locked. They assume everyone wants to greet their dog and everyone else's dog wants to play with it.
I usually walk multiple dogs at a time, 2 to 4, and I don't want any other dogs coming up to them, it makes for tangled leashes and not much time to react if the other dog is aggressive. So I usually carry a 5 foot sjambok (long flexible stick) and keep other dogs at a distance.
The other owner usually says things like "he just wants to play" or "he's never done that before". I just tell them to please get control of their dog, and will whack the ground hard in the direction of the dog to let the owner and the dog know I'll use the stick if the dog gets close enough. I go to areas requiring leashes in hopes that I'll be able to walk the dogs in peace, but some people think the rules don't apply to them.
The owner probably knew he didn't reel in his dog quickly enough, and took it out on you. I'd probably have done the same thing- I can never think of the really good things to say until after the fact, then I brood over it all the way home, what I should have said.
vickie