For me, QRs on the left make sense because I always dismount to my left and so, nearly always stand on the left side of the bike when I am not on it. So to remove a wheel for say a flat, the left hand levers simply make sense and the work easier and faster. Then when I have the wheel off, I can no longer stand the bike up so I lay it down. Right side up means chains stay on, the drive side doesn't see dirt and weeds. It is also the natural way to lay a bike down standing on the left. (Yes, you can stand a (fenderless) bike on its fork ends but that is hard on the dropout paint and I haven't owned a chromed and not painted fork bike in many years.)