This statement hardly merits the same level of proof as a scientific publication. The original post is an example of the obnoxious behavior you find on r/atheism.
They feel superior to and smarter than religious people. In this extreme case, the poster expresses feeling superior to people who died in a stampede that took place at a religious event.
Internet atheists who think they are superior to believers / Believers who think they are superior to atheists are two sides of the same coin.