Why would you pledge allegiance to an inanimate object? IF you are pledging to it as a symbol then you wouldn't have to say that yo additionally support the republic that it is a symbol for.

If you enjoy "getting better" it's something you can do all day and in every moment. This, plus it's long term investment value, makes it one of the more ideal things to want to enjoy.
If I enjoy getting stronger, I can enjoy any moment by finding a way to get stronger at something in that moment