Probably because they initially failed an element of officer selection. They will have been given options at all stages prior to entry but usually "forget" that element.I don't believe I made any assumptions. I commented on actual experience of people who joined not wanting to be Officers or having been steered down the Rating route only to Commission 2-3 years later. I had the same as a member of BRNC staff with two entrants being bussed from Raleigh.
Many fail AIB, don't want to wait a year, opt to join as a rating and then bleat about their AFCO "making me join as a rating". I'm surprised BRNC hasn't cottoned on to it. Then again, perhaps I'm not.