I can understand why the average Norwegian doesn't give much credence to conspiracy theories; chances are his leaders aren't being particularly conspiratorial (even if they have decided to replace him with a bunch of third world immigrants, they don't make a secret of it). But Americans seem particularly unfortunate in that they have almost Norwegian levels of trust combined with a fairly high degree of conspiratorial behaviour by their ruling class, and a media incredibly* deferential to that ruling class, so they are more easily taken advantage of than most.
*From the outside the deference of the US media is very striking. France, Germany, Britain etc all have much less deferential media ... . Whereas the free US media consistently shills for the Powers-that-Be.