They must put a big premium on climate. I grew up in Los Angeles and went to college in Riverside, and I'd rather play the public courses in Chicago and Indianopolis over either of them. Other than Rustic Canyon, I can't think of a lot of publics in L.A. that I really got excited about playing. As for Riverside, I have no idea why it would be included, unless they figure the "Riverside Area" casts a pretty wide net, as in all of Riverside County, plus a bit of San Bernardino. In actual Riverside you've got Oak Quarry and...well...Oak Quarry. If you throw in Moreno Valley Ranch, Oak Valley, whatever they're calling the former SCPGA courses now, and down to Temecula, there's really not much there, but that's stretching it. I'll take the Fort and Trophy Club over all of them.
Besides, climate ought to be offest by course conditions. Our growing season in the Midwest is shorter, but the rain and humidity tend to make for more well conditioned courses.