The problem is that most people seem to think scientific facts are value judgments. As a result, studies like heritability of IQ are still not accepted by all. It's like thinking lack of a god makes people immoral.
On the other hand, it's when people start attaching value judgments to scientific facts (e.g. "sensitivity to woowoo is heritable" + "sensitivity to woowoo is bad") that they step on the slippery slope. The only good way to deal with this is to see how close to a much more obvious value judgment one can get by logically reasoning on the facts. Usually a bit of reasoning can blow some of the more questionable ideas right out of the water.
(for good order note that "sensitivity to woowoo is heritable" is *not* a scientifically established fact but it makes a nice example)
This is difficult because logical reasoning is hampered when trying to reason on emotionally charged topics. Thus, people tend to flock round ideologies for fear reason might take them elsewhere. That's too bad because a factually and logically supported position is always better than an unfounded moral intuition, however noble or otherwise. Besides, often existing moral intuitions are corroborated.