Simple. Your assertion is incorrect and is posed simply as an insult. Any question phrased as "Why do <group Y> believe <belief system Y>?" is intended only to insult and belittle group X.
A similar insulting pseudo-question question would be "Why do huge numbers of Democrats believe the moon is made of green cheese?"
By definition, "backwoods parts of America" have few inhabitants--often fewer per county than a single Chicago precinct. In both black-majority and Hispanic-majority precincts in Chicago, the predominant religious denominations of the residents (Baptist for the black wards and Catholic for the Hispanic wards) regard rejection of evolution as a central tenet of their beliefs. Those are hardly "backwoods" areas.
Look, you may control the coast lines of the East and West,(out here in the waste lands, we call them welfare concentration camps) but stupid statements like that are what will get your butts thrown out of office in a heartbeat. Keep it up!