Some significant differences between civilian and military instructing I would reckon.
A military trainer gets a student who has been through culling programme after culling programme to get to a series of interviews where at least 50% more get culled. Flight training begins with chopping slow learners and more chopping and sends them off to ATC or transport or wherever. So the trainer is left with outstanding (their words) students, piece of cake. I don't know the figures, would it be 5% 10%
The Civvy instructor gets a student who has wandered in from who knows where, all sorts of backgrounds all sorts of reasons to want to learn to fly, all ages, all sorts of aptitude. No chopping here but finding a way to get them up to speed if at all possible . These $200 per hour students don't need an ace, they need and deserve an instructor who has been in their shoes.
I'm not saying a military guy can't make the transition, many have, but as in this case arrogance is not needed in GA