I agree. If you don't have good voice control over your dog, do not them them off leash.
Last night I went for a walk with my friend and her Shelite. We came up to a park with 2 border collies chacing a ball - their focus on that ball was amazing and they didn't even glace at our dogs. I've seen them before and they have good voice control over their dogs.
My friend lets her Shelite off leash - why I have no idea and he immediately runs up to the other dogs barking like crazy. She called him back but he kept on going. She said he knows those dogs and it was fine. The Sheltie joined into the game. I kept our distance (working on issues with Dakota) and worked on the "look at the dog".
I know I would have been upset if someone let their dog rush towards mine like that. I even came straight out and told my friend not to let her dog off leash because he does not have even a hint of a recall. She didn't care.
I even told her that if her dog came up to Dakota like that there is a possiblity that she would go after him. Didn't matter. Her dog meant no harm and that is the way it is.