
Why does he
need 2 hours exercise a day ?
I have Working Border Collies, a breed many"experts"state need lots of physical exercise if owned as pets. Wrong, a working sheepdog can work all day, but not all work is physical, most is mental control of the sheep and it isn't constant.
The same applies to breeds like Beagles, the more physical exercise like walking/running they get the more they need, and you get into a vicious circle.
Mental exercise tires a dog far quicker than walking/running/ball chasing. Getting a dog to use it's brain not only uses energy, but also acts as a calming measure & you get more control of your dogs behaviour.
How old was your dog when he was castrated ? How does he react when he sees another dog ? Does he bark, jump around, whine ???
Not excusing the other dogs' behaviour nor their owners having them off lead & not under control, however he may be unintentionally intimidating other dogs. You haven't given enough information about him being "hyper" to offer helpful advice.
I have seen overactive dogs behave in an almost manic way, in their excitement on seeing other dogs, not something many dogs appreciate