Let's say that you don't do something that you want to do, because you're not confident enough.

What is the difference between doing that thing, and improving your confidence which causes you to do that thing? What does it even mean to distinguish between those two cases?

And if improving your confidence doesn't cause you to do the thing in question, then what's the point?

Edit: On a reread, I might interpret you as saying that one might try (but fail) to change one's actions "directly", or one might attack the root cause, and having done so, succeed at changing one's actions thereby. If that's what you mean, then you're right.

However the advice to "change what you do" should not, I think, be interpreted as saying "ignore the root causes of your inaction"; that is not a charitable reading. The author of the Cracked article isn't railing against people who want to do a thing, but can't (due to e.g. lack of confidence); rather, his targets are people who just don't think that they need to be doing anything, because "what they are" is somehow sufficient.