IThe title is kinda funny ...

Hehe yeah you're right!

I've always found those old western movies to have the strangest name... They never seem to match up with their themes.

The title works on two levels: (1) literal: it is mentioned that Rocklin rides “tall (i.e., upright) in the saddle” like Red Cardell, who we later learn is his uncle; and (2) the phrase “tall in the saddle” is an idiomatic expression used to describe someone who appears confident, capable, and in control, especially in challenging or difficult situations. It originates from the image of a rider sitting tall and confidently in the saddle while on horseback — like Rocklin in this movie.