Religion
In reply to the discussion: How to Be an Atheist Without Being a Dick About It [View all]skepticscott
(13,029 posts)is that people believe that there's an actual god that dictates this stuff, and that his word must be obeyed to the best of their ability, now and forever, because it comes from "god" and therefore cannot be wrong, no matter how foolish and no matter what reason or evidence is brought to light. Humanist and other rational moral and ethical codes are not dictated by any unquestionable authority and are open to change based on the additional application of reason and new evidence. It is that unquestioning obedience by the religious to an authority with no authority that makes the difference.
And have you ever called a creationist a "dumbass" in real life? Would you? Then why do you think it's OK to do it on the internet (as you have)? Answer your own question.