It was yet another attempt by america to prove to the world that the steering wheel should be on the left, you should drive on the right side of the road, and that you should always run the opposite way you hang
Actually, the only countries that drive on the "wrong" side of the road are those that were English colonies at one point in the past. Europe etc. picked the same side America used to prevent English automobile manufacturers from sellijng their cars in Europe due to the dominance of the English automobile.
As for the bases, I hadn't thought about it before, but as I also cannot think of any LH throwing IF (outside of 1B), and as a majority of people are RH, that theory makes the most sense to me.