I believe that the first mistake in making an arguement is genralizing.
Like raytri said, dont get one comment and try to make the case that you "see many comments like these".
Whatever anyone says and how htey say it, its their own opinion.
I am a atheist and I dont tend to turn to this kind of attitude in religious discussions. i do believe that religion should not be given a free slate on things and just be respected, when htere is overwhelming proof on some things htat religion is not making the world a better place, but the attitude to make that arguement, I agree, has to be positive.