Not mentioned in article but I assumed car companies looked at what the majority went with and if any skew would swap to the other side. This would make filling potential quicker as most station have pumps that operate on both sides. This way if most cars had left side tanks then it would be advantageous to have a right side fill as slots are more likely to be open.
At many gas stations, at least in Europe, you can only drive trough in one direction. There is just no space to turn your car in the other direction without getting blocked if the station is busy.
I also always thought there was some kind of inofficial agreement between the various OEMs which one uses which side, so that it's about evenly spread in total. It would at least have made sense for maximizing gas station throughput.
