Just as your actions don't follow seamlessly from the theoretical understanding of what's the right thing to do, and just as the understanding of what is the right thing to do doesn't precisely reflect what really is the right thing to do, what you actually do doesn't always reflect what you really prefer. There are errors and biases at every step, and the role of theoretical and intuitive understanding of what you want is in implementing a stronger procedure that gets the things you care about done reliably, that fights the imperfections in the causes of your actions, and imperfections in itself, instead of using them as an excuse for failure.

Your true preference is not the ultimate source of you actions, and much less so where the cause of discrepancy with your own judgment is a known problem, one you don't accept as a part of yourself.