Umh, yes it is.
Lol how is it worse?
No, it really isn't. Consider this situation. Imagine socialism was the ideal solution for today's economy. Now consider two people, John and Chris. Chris had socialism shoved down his throat by parents, culture, friends etc.. Despite the fact that he hadn't a clue about what socialism stood for, he believed in it.
Now John is a harvard professor and has been lecturing about Socialism for years. He knows it inside out, he has flawless arguments and more often than not, knows exactly what he's talking about.
Now, according to you, the belief in itself is sufficient to define one's intelligence when it is clearly not the case here. This can easilly apply to theism and atheism.
Other than being closed minded, atheists generally posess an uncanny amount of ego and arrogance. They believe that they are truly superior than the rest. This type of arrogance quite accurately defines stupidity.Whereas theists, despite being closed minded fanatics, still posess some humility. To sum it up, I'd rather hang around with the latter if I wanted to have a good time.