This is at the root of your error. If you take knowing how to fly for granted, then all that remains is the application to the two different industries; and in that case you'd be right that a civilian background is automatically better for a civilian job.

But you shouldn't take flying for granted. It itself is a huge body of knowledge and ability, and all the particular applications on top of it can be learned in the training department and on the job. But the flying part is outside the scope of that, and only a fool would ignore it.