Jacob Bronowski pointed out that a commitment to discovering scientific truth entails a commitment to certain values, such as tolerance, integrity, and openness to ideas and to change. But there's more to it than that. Not only scientific discovery, but scientific understanding itself can depend on one's moral stance. Just look at the difficulty that creationists have in understanding what the theory of evolution says. Look at the prevalence of conspiracy theories among the supporters of bad causes, and how such people are systematically blind to rational argument about the facts of the matter. And, conversely, look at Galileo, whose factual truth-seeking forced him to question the Church's moral authority.
Why does this happen? We should not be surprised – at least, no more surprised than we are that, say, scientific and mathematical explanations are connected. The truth has structural unity as well as logical consistency, and I guess that no true explanation is entirely disconnected from any other. In particular, in order to understand the moral landscape in terms of a given set of values, one needs to understand some facts as being a certain way too, and vice versa. Moreover, I think it is a general principle that morally right values are connected in this way with true factual theories, and morally wrong values with false theories.