I just wanted to post and say one thing about this thread. There is no way in Hades I would have just stood by calling the police while someone mistreated a dog, any dog, let alone my own!! I'd have kicked that guy in the nuts so hard it would have taken him a WEEK to get back up. I would have been prepared to face the consequences of that too, because my dog's safety is worth it! Additionally, the law gives me the right to defend my family and property.
Instead of standing by and wringing my hands, waiting for someone else to "rescue me" I would have stepped up to the plate just like Andrew did! Taking into consideration that Andrew is a man, (and theoretically more physically matched to his dog's assailant) he could have done much more! He showed incredible restraint. I would not have been able to hold back as much as he did!
You did good Andrew, and you will have served as a deterrent to this idiot ever coming back to the park that your dogs and wife frequent. And hopefully this guy will think twice before he treats another animal (or human for that matter) in this way.