I have to be honest, i think it is a sterotypical generalistaion that christians especially consider anybody who do not subscribe to thier belief system as being evil. Indeed there was proof of this during the early period of christianity where followers of Ba'al ze bub ( an emergent alternative) ended up being outcast, and there god had his name twisted from Ba'al Ze bub (lord on high) to beelzubub (lord of the flies). and as a result the god was deemed as the anti christ, almost as a way of evolving a survival strategy for ther religion by using rhetoric, lies and mis-information.
As to whether atheists do bad things because of unbelief is unfounded. Yes there are and have been bad athesits ( just look at Stalin) but on the whole we experience low crime rates, lower divorce, and happier home lives. You only have to look at scandinavia for that who have some of the lowest crime rates in the world, but the highest rate of atheists/agnostics