Well, I did say there are "roughly" two kinds. I agree it's a simplification, but the main point stands. There are "nerds" on both sides, and those extremists may have more in common with each other than with the masses on either side who couldn't care less about religion, philosophy, science, or ideas in general. That's not to say the extremists are alike also in the religious apologist's sense. But there's a kernel of truth there which I think is worth pointing out.

What's surprising, then, is that there are tribal dynamics in all groups, and the leaders even of opposite groups may be "shadows" of each other.