If you have or are retiring from the military then you won't be dropping mil leave. So, United doesn't have to worry about that with you. If you are separating after your initial pilot training commitment you won't be getting a call from United because they are automatically making a lot of assumptions. Those being:

1. You will be going to the guard or reserves.

2. You'll be dropping up to 5 years of mil leave.

Therefore, they will not be calling you for an interview because they don't want to deal with mil leave. In my book that is discrimination. It might be legal (not sure if it is or not), but that doesn't mean that it isn't discrimination.