You do know that food and toys are a no no in a dog park and is almost a guarantee for a dog fight? It has nothing to do with dogs that are intact or neutered. The only cure for that is to remove all food / toys or remove your dog.
Also, I wonder if you know that hormones can have a calming affect on a mature dog that starts to show up at two years or older? Nothing like calm confidence if you have ever seen it.
Time itself is a very powerful component of learning. So learn to wait. Learn to forgive. Learn to backup. It's all necessary for learning.
Teach! Teach! Teach! Be fair to your dog!