desu, i don't disagree with anything you said.
i work as a bike messenger and have people to yell at me to ride on the side walk all the time. people are shitters. ultimately, i'm the actual person on a bike, i'm gonna know more about how i should ride that bike than the cager because i'm the one fucking riding. i've had my share of shitter cops who dont know the actual laws too
and yeah, people should decide based on factors. i wont blame someone whos a newer cyclist sticking on sidewalks cause they dont have the confidence for roads yet, provided they take it slow but one of those conditions is if you have a motor on your bike. its blatantly unsafe all around, which is why its illegal virtually everywhere in the states. if your experience/surroundings/whatever make you decide that you want to ride on the sidewalk, okay. go for it. do it on a regular fucking bike. be responsible and use the right tool for the job