The attitude is due to ingrained religious belief.
An international study conducted by Nature Human Behavior, a journal, revealed that atheists are suspected in greater numbers of doing evil deeds compared to Christians, Buddhists, Muslims and Hindus. The study discovered that atheists are widely regarded as more likely morally depraved. They are also considered as dangerous.
The study had 3,000 individuals scattered across 13 countries as respondents. The list of countries ranged from secular ones like Netherlands and China to nations predominantly made of religious believers like India and the United States. All countries had populations made up of a mix of Buddhists, Muslims, Hindus, Christians and the non-religious.
The results of the study are surprising as even as the world is slowly growing secular, many of its inhabitants, including to the researchers' shock, atheists, too subscribe to the view that people will behave badly unless they are afraid of being punished by the gods. The results clearly display that religious belief is intuitively believed all over the globe to be an important safeguard against immoral conduct. Participants of the study were provided a description of one fictional evildoer who had tortured animals when he was a child. The person then grows up and becomes a teacher. He mutilates and murders five poor people who were homeless. Half of the study group was questioned as to how likely the evil person believed in religion, and other half was questioned about the probabilities of him being an atheist.
To the surprise of the researchers, the team discovered that people were twice as probable to make the assumption that the depraved individual described above is an atheist. Will Gervais, psychology professor, University of Kentucky, and the co-author of the report, said that it was a shock to see atheists holding similar views. He continued on to say that he suspects this result came from a prevalence of the deeply entrenched religious mores. These hold true for even extremely secular societies as well. People continued to hold the notion that religion could be a moral safeguard.
Two countries buckled the trend- New Zealand and Finland. Only in these two secular countries were there inconclusive anti-atheist prejudice. Atheists were most distrusted in religious countries liken United States and the United Arab Emirates. It is much lower in the secular nations. The authors of the study also pointed out that in a number of countries, atheism can be fatal for people holding such views.