Every day, we see advertisement after advertisement, and most of these make zero sense from any logical point of view. Catch the wave, how to spell relief, Beyonce with a gold "upgrade" bling in her mouth, lies about cable and satellite TV plans, lies about cellphone service diet remedies, cars, everything. And you ask "How can any one smart enough to earn enough to buy these things believe this crap?".
But the truth is, as the inventor of modern propaganda, WWI AG Mitchell Palmer knew, and as Josef Goebbles learned from him, all you have to do is spout lies, innuendos and mistruths again and again and again, and eventually people start to believe them. Next thing you know, there they are, sitting in their Hummer and voting for morons like Juniorbush.
Hitler called this "The Big Lie". Lie big and repeat it forever and most of the time, you will find people will start to believe it. It helps when you focus on people who already have shown that they will believe stuff with no proof, like many religions.