It is one of religion’s greatest successes, which is being able to equate morality to religiosity. There is no evidence that the religious are any more moral than or upright than their non-religious counterparts, but as we know with religion, something doesn’t have to be true for people to believe it wholeheartedly.
So this permeates into a society where people automatically think atheists are bad people, and that is the results this study so clearly brings out.
Conducted by the psychology department at Nottingham Trent University, the study sought to discover how prevalent prejudice against atheists is in society, including even among atheists themselves.
“Anti-atheist prejudice is not confined either to dominantly religious countries or to religious individuals but rather appears to be a robust judgment about atheists.” The study concludes.
It shows that anti-theist prejudice is not even necessarily reserved to religious people, showing how a dominant culture can affect even those outside the norm.
The Independent further reports…

The researchers presented the participants with a story about a man who reversed car into a van one day and didn’t leave his insurance details.
Later on, when he found a wallet, he removed the money from it for himself – and respondents thought it more likely the man was atheist.
The university said the findings “suggest anti-atheist distrust is deeply and culturally ingrained regardless of an individual’s group membership”.
They added: “Looking to the future, it is also important to explore how these perceptions and attitudes toward atheists manifest behaviourally, whether people act on these prejudices and in what contexts. It is only once the nature and extent of the issue is better understood that we can take measures to address it.”

When people heard of a bad deed being committed, they are more likely to assume the perpetrator is an atheist. Which is remotely far from true, but that is how prejudice works.
In the United States for instance, a prison inmate is far more likely to be religious than non-religious, even when you control for the large disparity between the number of people belonging to either camp. But it still doesn’t prevent atheists from being the least likely to hold public office, another measure of the deep unsubstantiated prejudice against them.