I don't think so. I am an atheist and my reasons for being one are mostly due to religion never having a huge part in my life. I think it partly depends on why a person became an atheist as well. They might have been someone who pondered upon the question of religion and theology a lot longer than something else and concluded that religion is bad/futile in their opinion. It does not correlate with intelligence directly in my opinion but simply more upon how much has one person thought about religion. There are plenty of people who understand that a lot of shenanigans happening in a church, a temple or a mosque are not a true representation of what their holy books are trying to teach. I don't know about you, but I would never call a level headed person who takes the core principles of most religions regarding being a kind and thoughtful person as an idiot. Plenty of atheists in the world who have not really done extraordinary things in their lives (including me) and can be pretty stupid as well. There are atheists who actually wish to turn atheism into a cult as well and spit vitriol against religious people or belittle them. There are atheists who simply follow it as a trend because they probably liked how someone like Richard Dawkins or Stephen Fry mocked religion. Now those two gentlemen are highly intelligent people who are atheists. But everyone who is simply taking their word as the truth without critically examining it might be an atheist, but not necessarily intelligent. Intelligent people don't really do that.
Of course that does not mean that I personally don't criticize religion. But I try and look at its importance from a cultural perspective as well. I do not support the idea of branding Islam as a violent religion when looking at the real history of modern terrorism throws much light on how there is a geopolitical background to Islamic extremism as well. Psychology plays a huge role in all this. People are more vulnerable to manipulation when they are desperate. They feel like they all need to get together to overcome whatever problem their community is facing. And it is very easy for a highly aggressive "us against them" mentality to take hold in that moment. I do think that this aspect of human nature contributes to us doing bad, irrational things as well and religion is just one institution taking advantage of that.