To add to the debate I am also a motorcyclist, you have to get off on the left side because that's where the stand is. When stopping it is always recommended to cover the rear brake in case of a collision from behind, holding the front brake will pitch you over the bars. Starting off on a hill it is also recommended to hold the bike on the rear brake to give max control over the throttle.
So moving to a bike it is natural to unclip and put the left foot down, also to mount from the left so the right foot is first on the pedal.