Sounds like BS to me. If the company was so short that the result of you not getting on the flight was a cancellation then the company would have positive spaced you. You said other non revs got on so the company would have no problem bumping off a non rev to get you on. Again, sounds like BS to me.
No, because the "company" (Pinnacle) will not positive space you if you can't get to work. You're allowed 2 call-in-honest events in a rolling 12 monhts. After that, you will be disciplined. They'll never positive space you from home to get to work. Instead, you'll get a lecture that commuting is a choice. They WILL positive space you for deadheads, which are work related movements within a trip. But getting TO work (as in commuting) is entirely up to you, and I don't know a single regional under Delta that will positive space you for your commute flight to work.