There are two atheist "memes" (to use a jargon term) that seem to me to be in prima facie conflict. I will not claim to be able to cite chapter and verse showing that the same atheist uses both of these memes. But I'm quite sure that there are atheists out there who have done so.
So these are not exact quotes from anyone but approximate statements that reflect things that I, and I suspect you, dear Reader, have heard and read.
Atheist meme #1: It is offensive to imply that being an atheist is in any way detrimental to being a moral person. Atheists can be just as moral as religious people.
Keep your eye on the ball. The question of what is meant by "just as moral" will be crucial.
Atheist meme #2: The idea that man is in any way special is speciesism derived from religious ideas like the image of God. Once we get rid of those religious concepts we can see that man is just another animal, though a highly evolved one. Man's continuity with the animals means that abortion, euthanasia, killing those in "vegetative states," and even infanticide are all "on the table" for ethical debate. The decision in specific cases should be made on the basis of utilitarian considerations without any notion that human life per se is valuable.
It should be pretty obvious that the proposals in atheist meme #2 are socially radical. They represent a departure from what a lot of people for a long time in Western society have thought of as moral behavior. Yet atheist meme #2 says that, once you are an atheist, you should consider them to be viable options.
Prima facie, this conflicts with atheist meme #1. It's pretty obvious that, if atheist meme #2 is true, atheist meme #1 is false: Atheism does make you a less moral person if atheism leads you to consider doing all those things or even advocating them.
Suppose someone wanted to hold both of these to be true. What could he say? He could try to say that, since the ethical system outlined in atheist meme #2 is actually correct, atheism doesn't really make you less moral. It just leads you to redefine what constitutes morality so that it allows things that previously (traditionally, according to Judeo-Christian morality, etc.) were not allowed.
The problem with that response is that it turns atheist meme #1 into a pointless tautology. If atheist meme #1 has a point in communication, it must be either to reassure people about atheist morals or to shame those who question them. Neither of these ends is served if "moral" in atheist meme #1 could mean "Moral according to norms radically redefined by atheists themselves." If that's the only meaning, atheist meme #1 is compatible with, say, finding that atheists are bank robbers at a much higher rate than the general populace, so long as they are following some atheist redefinition of morality that makes it okay to rob banks. But that would certainly undermine the point (at least if enough people noticed), because then people would decide that atheists qua atheists are less likely to be "nice people."
What this shows is that anyone who trots out atheist meme #1 but also plans to advocate atheist meme #2 is doing a bait and switch. Start by protesting about the morality of atheists. Trust that your audience will be lulled into accepting this claim by the fact that the intellectual atheists you intend to hold up for their consideration aren't right now breaking any laws or personally engaging in any gruesome actions (even if they are quietly, academically advocating them). They look like "nice people." Then later argue for the "enlightened," utilitarian ethics that you actually believe.
I have sometimes wondered, when atheists complain (a la meme #1) that others think they are less moral than theists, what they would say if asked, "What do you think of abortion, infanticide and euthanasia? Is your position on these matters at all influenced by your atheism? If yes, and if I consider your position grossly immoral, then why should you be offended to learn that I consider that your atheism makes you less moral?"
The funny thing is that I actually believe that the true positions on these issues are available by the natural light and hence do not require theism to understand. (Though theism helps. Human beings always find it useful to have more sources of information than strictly necessary.) I examined some of these issues in this essay. In Western society, however, the brand of atheism most commonly held is not some sort of virtuous, Platonic atheism that cleaves to the Good and accesses the natural light but rather some version of naturalism. And that is highly detrimental to moral insight.
I present my readers with the conflict between meme #1 and meme #2 in the hopes that it may be useful, either in talking with atheists or talking to others about atheism.