I don't find it unusual. He's building rapport with a reader base by referencing american pop culture, and possibly knowing that many linkbait-y blogs will jump on this as a hook. Nothing too weird, but imo more of a way to bring publicity to his rebuttal than an actual argument point.

To me, it seemed rhetorically counter-productive, but its a minor point really.

I don't see why using a fictional character to make this point is harmful. A much wider range of people know who Indiana Jones is than who (take your pick of experts consulted with by a government) is.

Because he chose a more widely known (albeit fictional) example, more people are able to better grasp the idea he is presenting. It's just good communication.

Another good reason for using fictional examples when it fits your argument is that their contexts are more limited and less likely to trip context-driven ideological or emotional biases.