…and no Native American man with any self-respect that I know of would ever choose "boy" as part of their name.
You don't really choose your own name. It really depends on the tribe and tradition.
For instance, there was a Lakota man named "Young Man Afraid Of His Horses". I doubt he would have chosen that name for himself. A person was usually renamed through life, depending on different situations. Birth, a formal name, a name given during an illness, a name given after puberty and so on are just a couple examples of when another name was declared.
An elder would usually give the name, or someone else of equal importance where the name giver would hold ceremony and name an inidividual through a vision, or what Spirit suggested.
Many individuals would be known as one name in one tribe, and be called something totally different in another.
Of course every tribe had their traditions on names, so what I said may or may not qualify as truth depending on the tradition.
Pony Boy may or may not have chosen his own name. Or maybe he did. Who knows?
As for Native American Horsemanship, its a "form" of natural horsemanship that requires money in order to be learned. Just like everything else. I like Pony Boy's techniques, but only because I learned that they were similar to what I was taught. Same tree, different branch. Much like a lot of correct training is.