No, it doesn't do that.
It asks for BOTH FWD and AFT doors, and this is not a bug, it's how is supposed to work.
The option about what loader to use at the *parking* spot, only refers to the kind of loader used. It doesn't mean the whole service, which is composed by loader+train. When you select "None" as loader, it doesn't mean you don't want the whole service, it means just that: there will be no loader, but the service will still work with the train only, assuming the baggage will be loaded by hand, the reason for this option is to fix problems with parking spots too small for even the conveyor belt to be able to manoeuvre, is not intended to remove a service from a door altogether.
To remove the whole service from a door, you have to disable the door on the airplane itself, using the aircraft configuration editor, not the parking editor.
