As Hume taught nearly three hundred years ago, the "ought" does not follow from the "is". A moral decision may of course be at least partially informed by factual evidence, but factual evidence alone is insufficient since the moral decision must ultimately follow from distinctly moral premises.
Your appeal to science as an authority is therefore misplaced. Moreover, such appeals typically have a dubious provenance (e.g. the conspiracy theorists who claim "science" in support of their contention that cannabis cures cancer - despite the obvious fact that cannabis didn't save Bob Marley from jammin his toe in death's door).
It is the moral premises that must be challenged. In a properly Liberal society, people have rights of free speech, free association and free trade and those things must be propagated with moral arguments standing on moral premises.
Update: the comment didn't get through the filters for some reason.