It is hard not to be over protective of our dogs, esp. puppies! Chances are they would have been fine, and sometimes dogs just need to work things out for themselves, but still once, the owners saw that you did not like their dog knocking yours over, they should have tried to keep their dog enertained elsewhere. You romoved Zeke from the situation, the least they could have done was prevented it from happening again.
My mom has had a few issues at the dog park. Dazzi out of the blue has gone after a dog for no apparant reason. When she does, they either leave, or Dazzi is put in the time out kennel, away from the other dogs.
Once a male husky had Taggert pinned down and was trying to "hump" him. The kid with the dog did nothing. My mom pulled the Husky off and he tried to snap at her. She swatted him on the butt, and said "no!" The boy then was mad at her for "Hitting" his dog. Personally, I would not consider a light swat "hitting" a dog, and second of all, control your dog and I won't touch it...simple as that.
Glad Zeke is okay!