A 2007 study from the University of Minnesota looked at the acceptance of atheists in American society. Using new national survey data, it shows atheists are less likely to be accepted, publicly and privately, than any others from a long list of ethnic, religious, and other minority groups.
It's safe to assume that atheists are completely accepting of their fellow atheists' religious beliefs -- or, more accurately in this case, their lack thereof. That leaves only religious people with the distrust of atheists.
Atheists are so distrusted and despised by people of faith that less than half of all Americans would be willing to vote for an atheist to be their President. When faced with a laundry list of religions and ethnic minorities, almost forty percent feel that atheists do not at all agree with their vision of America (thirteen percentage points higher than the next most unagreeable group). When asked if they would disapprove if their child wanted to marry a member of this group, 47.6% disapprove of their child marrying an atheist (fourteen percentage points higher than those who would disapprove of their child marrying a Muslim, the second most disapproved group). These numbers are even higher among Americans of faith than they are in the general population.
While most religions preach tolerance and acceptance, it turns out most of their believers are anything but tolerant when it comes to atheists. Surprisingly, they're even more tolerant of people of different faiths, even though an atheist is the least likely to proselytize them.
Self-interest would dictate that a religious person would prefer to have an atheist in the Oval Office than someone of a different faith because the atheist would be the least likely to allow religious convictions to influence the decisions they make as President. Surprisingly, it turns out the atheist would be the last person they would want for their President.
Most parents would want their children to marry an intelligent spouse. Since atheists, on average, have an IQ almost six points higher than a religious person, it would seem that an atheist would be the more desirable spouse. Apparently, however, parents would prefer their child marry someone of lower intelligence over marrying an atheist.
While it's well and good to preach tolerance from the pulpit, god forbid you practice tolerance in your life.