Tut, tut! I said no such thing. We're very specialized for thinking, obviously. I just said we aren't optimized for it: on average, we demonstrably can get much smarter than we are now.
Shouldn't the forces of nat selection weed out all but the best, fittest etc?
Not at all. It just provides a bias towards (for example) greater intelligence. It's not a yes/no judgment on the fitness of each and every creature; it's more of a 1.0001 to 1.0000 advantage for one allele over another. That plus time is all that's required.
How can people be (largely, though not exlusively) unspecialized? It almost looks like people were just dumped here from someplace else.
Woah, there. In your first comment, you held up humans as an example of evolution, and pointed to the mosquitoes as counterexamples. Now you're saying that humans are bucking some expected trend. Which is it?