If it is genetic, there should be research and a quest for a "cure" "Help fix Paul Krugman.. Donate today, and save someone you love from becoming a fucking idiot."
A study of 2,000 adolescents does not prove anything.
Even if it were true.. Government indoctrination has at least as much to do with it as genetics. It's telling that you can put someone in a college setting for a couple of years and turn them into a liberal with amazing precision. They like to portray this as becoming "smart" I'd agree with that, except their prescriptions do not work. Therefore, it must be something else.