As far as that CFI, it’s always been spelled out in AC 90-66. Straight-in traffic does not have priority over traffic established in the pattern and should coordinate. In many years, I can remember only one time where someone got annoyed with my practice instrument approach and I backed off at a safe distance. In a small airplane, it isn’t a big deal. But if I’m on the downwind and hear a jet call a straight-in, I will immediately let him know I will follow. There’s no sense in making a jet abandon a safe straight-in and make it join a traffic pattern with airplane’s half it’s groundspeed.