I have to say that I have had my current dogs offleash in regular parks, against the bylaws, but my dogs are very social, without any reservation. My previous lab was very dog aggressive and we avoided dogs with all our ability. Personally, I think you were irresponsible letting a dog with aggression issues offleash in a public area.
On top of that, from your description, your dogs had a bad recall, which means they shouldn't have been let off the leash at all, regardless of aggression or not. There is no way you can be in complete control of your dogs off leash without a 100% recall. When other people and other dogs are involved, you have to have complete control, to avoid incidents like these, or at least to minimize the risk.
I don't know what you expect us to say here.
