How can a user create an entry that is only enabled for 1 locale?
I have tried disabling each locale in the channel settings, but, then the user is required to enable it for their own locale when publishing.


That's the only way to pull off what you're looking for in Craft 2.

With the upcoming Craft 3 refactoring, it would be much easier to pull of with a new event that a plugin could listen to and alter the behavior.

Feel free to make a feature request as well.