I doubt it's anything to do with protecting you.

You have to remember that, like human males, entire dogs have testosterone oozing around their bodies. Testosterone, among other things, can make dogs somewhat braver than they would be if they were female.

Take away that testosterone through neutering and you can tend to find that you've taken away their Balls in more ways than one

Rather than wasting time and money on "alternative" remedies, you'd do better to think about training classes, where he can work on his social skills with other dogs and get his confidence so he feels a bit braver