It's an optimization. Making bikes come to a complete stop makes them really slow for a lot more time before, during, and after the stop sign. It's the equivalent of stopping your car, putting it in park, turning off the ignition, restarting the car, putting it in gear, and then going through the intersection. It certainly doesn't make anyone safer to make cyclists stop like cars.
As for cyclists yielding instead of stopping, it probably does make things confusing for drivers. As a professional trainer you no doubt know that the vast majority of American drivers are shit. Unlike most civilized nations, an uncle, or maybe even a pet, can be your driving instructor in the U.S. So making the system complicated with more exceptions to apparent rules might not be such a great idea. Yes, this is coddling stupid people who probably shouldn't be allowed to operate heavy machinery in the first place, but we should be used to this. It's what defensive driving is all about.
The other thing, is that since a bike isn't heavy machinery, the penalty for others when the cyclist makes a mistake, is very low compared to car-on-cyclist mistakes.
But until the roads are better shared among drivers and cyclists, it's difficult to get cyclists off sidewalks, and in particular speeding cyclists off multi-use paths. They should be using streets or dedicated bike lanes instead.
even though it's generally illegal for them to be there. And difficult to get speeding cyclists off multi-use pathways, when they should be on roads instead, but only if it's safe.