The map is interesting. Its clearly an attempt to discuss cultural patterns and like all generalizations has of course some truth to it. I think though Florida is a very wierd place. Miami area, West Palm-Fort Lauderdale, Tampa, the Keys, and Northern Florida are very distinct.
I think an argument could also be made to make a gay culture in parts of California, Rhode Island, New York, Florida (the keys). You could make a hell of an argument for a distinct Cuban culture in Miami-a pronounced Jewish culture concentration in Miami and New York City, a pronounced Haitiens presence in Florida, then the Latino spread of population in California and only certain Southern states.
I guess it depends on what dominant cultural patterns you look for. I think you could do one with a fundamentalist Christian region and an urban-rural split as dominant cultures.
I do think its accurate in the way it defines the dominant cultural traits it singles out. Its an interesting discussion starter. Its certainly fluid and could be added to or split into some more overlapping cultural patterns but it does a good job.