I also agree w/ everyone else here & the owner of the JRT.
I always walk my dogs on a leash unless at home in my yard & in some hiking areas. You never know what may happen. The owner has every right to go after you for that. I would probably do the same!

The second dog may have went crazy the second time cause either she sensed the dog may have been mean (that is why the owner kept it ona leash probably) &/or because she saw your other dog go after that dog.

You do not let your dogs run free just cause yours are nice you have to think about other dogs or even objects, cars etc.. Even the very best dog can be a dog once in a while & have their instincts take off, like chasing a squirell in the road or running away after something, or attacking another dog.