I'm inclined to agree. Since the differentiator is expected drive, one can reasonably conclude that autodidactic is more likely to have it. It is what got them this far. While many graduates also fit that description, it is difficult to filter them from those who graduated only due to social pressures and income dreams.

For the theoretical programmers out there, you may recall that the future is independent of the past, given the present. I'm not certain it is worth hiring anyone based on their history. I would look to what they can offer today, and try to discern from that where they are headed in the future. It takes more effort this way, but you get what you give.