Human well-being is not a random phenomenon. It depends on many factors - ranging from genetics and neurobiology to sociology and economics. But, clearly, there are scientific truths to be known about how we can flourish in this world. Wherever we can have an impact on the well-being of others, questions of morality apply.
Everything we do is for the purpose of altering consciousness. We form friendships so that we can feel certain emotions, like love, and avoid others, like loneliness. We eat specific foods to enjoy their fleeting presence on our tongues. We read for the pleasure of thinking another person's thoughts.
Tolerance, openness to argument, openness to self-doubt, willingness to see other people's points of view - these are very liberal and enlightened values that people are right to hold, but we can't allow them to delude us to the point where we can't recognise people who are needlessly perpetrating human misery.
I consistently encounter people in academic settings and scientists and journalists who feel that you can't say that anyone is wrong in any deep sense about morality, or with regard to what they value in life. I think this doubt about the application of science and reason to questions of value is really quite dangerous.