Slashdot is a forum where the majority of users are IT professionals, our brains able to deal with some unbelievably complex problem solving that people outside of IT consider a type of magic. Most of us have been hailed as geniuses by our friends and family.
Stray outside of IT related issues however, and the comments here vary widely from occasionally insightful to completely idiotic. You know it. I know it. Everyone here knows it.
And it's not just us. From Thomas Edison to Richard Dawkins, remove them from their field(s) of expertise and they end up being advocates of really shitty ideas.
The point is Carson is intelligent in his field, but that doesn't make him qualified in anything else. I'm not saying it precludes him from being smart in other fields, but it explains why in many areas he's said some really dumb stuff.