Why do I attract stupidity?

First and foremost, I must say that I laud Swedes for their commitment to learning much of the English language. Nearly everyone I ask a question in English (do you have international calling cards, where can I find a map, why is everyone so blonde here?) is able to answer me with little to no difficulty. It seems, though, when I begin to engage in a deeper conversation than the normal "is this your first time in Sweden? How do you like it? How long are you here?" etc, that there are just as many idiots present in Scandinavia as there are in the US perhaps more.

Granted, I've met some very intelligent Swedes that I would delight in talking to all day long (one of them being local indie star Tobias Froberg, his fiancé Sondra, and Michael, the music producer of Scandinavia's largest theme park, to name a few) but I have certainly had the unfortunate displeasure of having lengthy repeated conversations with some who are no brighter than a brick wall that is suffering from a growing and relentless dementia. As my father would say, "about as dumb as a bag of hammers." Now my question is this: is it the language barrier or just genuine lack of appropriately firing neurons that account for the sheer stupidity? Do these same people think that yours truly is a moron as well? Finally, how can I spot these people before engaging in conversation or how to keep it to a minimum with those I cannot avoid?

Yes, I realize this post is one full of brash language and perhaps a false sense of superiority
by yet another complacent American, but I'm just telling it the way it is. Any thoughts?