Take for example, Anders Breivik, the Swedish mass murderer and white supremacist who killed dozens of his countrymen, while declaring himself a member of the Knights Templar, and expressing his hope that his actions would ignite a new crusade against Muslims in Europe. Even Pat Robertson couldn't claim that guy was an "atheist", though it seems that there is always a new effort to do so, whenever one of these violent events occurs.
It is, of course, necessary to note, at this point that Sikhs are NOT Muslims, though mental midgets such as Mr. Page, probably thought they were. He was reported, for example, to have a "9-11" tattoo on his arm, but nobody has ever even remotely hinted at the possibility that any Sikhs were involved with 9-11. That's because none were involved. However, because they wear turbans and look similar to some people in the Middle East, Sikhs are often confused with "muslims" and "arabs", and other categories which likewise have nothing to do with them.
So, of course, it might make sense to blame Mr. Page's appalling ignorance of human geography. It would also make sense to blame his apparently right-wing xenophobia against people he wrongly thought were associated with 9-11. It would even make sense to blame Mr. Page's probably insufficiently treated alcohol and other mental problems. But it would make no sense to blame atheists, since Mr. Page is likely no more of an atheist than Sikh is a follower of Islam.