I don't know the answer to your question, but I don't think it's stupid. We should trust our sniff tests on these types of studies more often, especially when there is a potentially not-too-distant political, economic, or social consequence attached to the conclusion.

I personally think this is a common tactic by academics -- put out something that has a clearly false-as-phrased conclusion and then get lost in a maze of dense data and opaque language, come out disoriented, and make some conclusion like this that's pretty clearly invalid if you're willing to step away. The authors somehow convince themselves that the obvious conclusion is incorrect (often by redefining words) and then accuse anyone who dares to point out that the conclusion is a sham of being a luddite and anti-intellectual.