Atheism is just the belief that there is no god. Its not a structured political doctrine that requires following certain beliefs. The opposite would be a theist that believes that a god does exist. Personally i dont have a problem with either view, theists tend to have structured religious doctrine, so their behaviour might be different to the norm, but so long as they are not murdering or harassing people there shouldnt be any issue. Today though the most religiously obnoxious people are atheists. To be perfectly fair thought most arent atheist they are in fact jews, so the rest of the non believers unfortunately get lumped in with them just like how christians get lumped in with obnoxious jewish televangelists that tell christians to donate to israel.