Why does the R2L motion seem odd to you? It isn't unnatural or odd. Just not the same as Mario. I suspect that his hypothesis is bunk.

Perhaps originally they were theatrical shorts, but I know almost everyone here watched them on TV. Even as rebroadcast packages they shaped every other cartoon on this list. Before the Simpsons did it, Bugs and Daffy did it.

How is M not Merrie Melodies? Oh because you are a terrible person with no idea about cartoons.

I think you need to buy an atlas.