I know real life shouldn't matter that much, but......when actually on a bike and stopping, you tend to put the kickstand down and the weight of the bike leans into it as you also lean in that direction. Getting off the bike to the right is just so awkward and the fear of knocking your bike over the other direction and grounding the vehicle exists.
For gameplay purposes, if the left side is obstructed, I have seen my character jump out on the right, same with cars.
This has been irking me for a while as well. The other reason for getting off on the left side of a motorcycle (other than the main great reason above, which is absolutely correct - the kickstand / tipping over) -- at least on Japanese bikes, is that the front brake lever is on the right handlebar... makes for a great safety measure to squeeze if your bike starts to move (for whatever reason) when getting on/off. Now in the Cyberpunk world, it seems that these bikes have advanced stability control. However, for a person who rides, the left is the only way to go - no matter the year or era ;p .