Sorry, SDAI
I can think of too many exceptions on both sides for that theory to hold up very well. Confusing creation only with the development of physical goods is a mistake made more often on the socialist side. Ideas are the core of all progress.
IMO, the real answer is a lot simpler: journalists go to journalism schools, where the academic left fills their heads with crap. Unfortunately, this is true for a lot of other professions, including teaching. Damn few journalists consider themselves conservatives. Or educators, for that matter.
I personally think a big problem in our country is college campuses which tout diversity in everything except ideas, which are solidly on the Left.