There's no doubt that the situation could have been handled better. However this often happens when enthusiasm takes over before a dog is truly ready.

Put yourself in their place and imagine how you would feel if you finally had Zeke trained not to try to play with other dogs and then someone else's dog did the same thing to Zeke. It can set them back months in training.

It's a good idea to go back to your obedience classes and stay with them until Zeke is completely under control.

It's just a small setback. Next time will be better.