It's a flippant way of putting it, but it's basically true: those who want someone average, someone like the people they know, and those who think a leader ought to be a little smarter, a little better than the rest of us.
The first kind of voter trusts someone based on how they appear. They don't care that Wasilla made rape victims pay for their own rape kits under Palin, or that McCain voted against a law that would require the states to pay for rape kits, just as they do for DNA testing and fingerprinting in any other crime. They don't care that McCain released an ad attacking Obama for supporting teaching kindergarteners the difference between "good touch" and "bad touch" (the entirety of the "comprehensive" sex-ed program for primary school).
No, McCain, and especially Palin, act like the good folks they know, so they must be trustworthy. And they say they're on the side of law and order and family, so it must be true, no matter how they act to the contrary. After all, nobody could pretend to be "good folks", right? It's not like we've spent the last eight years under a President who got into office on the strength of his ability to act like good folks, and then proceeded to completely screw over the country in every way imaginable by an incredible combination of bungling and corruption.
No, we know that McCain and Palin can be trusted to run the country no matter what they do, because they told us so. And we know that Obama is an evil schemer, because the people who say one thing and do another told us so.