Our moral sense is only one of the many things that motivate us.

I'm talking about extrapolated morality, which is not the same thing as moral sense (i.e. judgments accessible on human level without doing much more computation). This extrapolated morality determines what should motivate you, but of course it's not what does motivate you, and neither is non-extrapolated moral sense. In this sense it's incorrect to oppose extrapolated morality (you shouldn't do it), but you are in actuality motivated by other things, so you'll probably act incorrectly (in this sense).