He clearly overreacted and was aggressive and scared you. It might be that he’s just an awful man or it may be that it was a panicked reaction to the fear of seeing his child knocked down by a dog, which he may well have thought was an attack by the dog. we can’t know and it was probably a little of both.
Out if interest, what breed is your dog? All have the potential to be dangerous (and all to be lovely) but there’s a real difference between having a cockerpoo jump up and an XL bully.
But dog owners are getting worse. You need to train a dog well and then be responsible for it at all times. Leads on unless safe to be off. Not letting dogs rush up to strangers, etc. etc. It protects other people, other animals, and yourself and your dog.
We hear of so many awful dog attacks nowadays. I suspect many of their owners would have labelled their dogs as ‘friendly’ and ‘playful’, right up until the point they suddenly weren’t.
I live in the countryside, I know of many examples of arrogant owners of badly trained dogs who ignore signs to keep them on leads in fields and such. They know better than the farmers and the signs, and their daring little dog would never do that, and if he does start chasing sheep, he’s ‘just playing’. It’s irresponsible and dangerous. If you want an animal you have to be responsible for it.