If you are religious, and you see two people, an atheist and a member of your religion, doing the same *exact* action, you will always rate the atheist worse.
Philosopher Paul Draper writes: “The most robust prejudice correlated with religiosity is prejudice against atheists. [In a study by Jennifer C. Wright] Christian and atheist actors were portrayed in one condition as performing IDENTICAL immoral actions. Those actors portrayed as atheists were appraised significantly more negatively than those actors portrayed as Christians.
In another condition, atheist actors portrayed as performing supererogatory [morally good] actions were regarded as less praiseworthy than their Christian counterparts performing IDENTICAL actions.”
This is consistent with other ratings given by the US public, as seen in this 2014 Pew survey.