As a main instigator here, I’ll chime in and state that I actually don’t mind shorts.
My qualm with open toed shoes has to do with oxygen recycling and re-circulation of pressurized air on planes. I also want to say that I don’t care where you wear anything otherwise, do you. Planes are just one of those things where you are impacting others with your actions.
Dress for your job, if you don’t wear a watch and teach surf lessons at turtle bay, have at it with the flops.