Bull... If you have an Atheist, a Jew, a Christian, a Buddhist, a Hindu and a Muslim hanging out together, they could very well say that they have common moral values.... And they probably do for the most part. I would imagine they would be in common agreement that killing, theft, rape and other things like that are wrong... where charity, happiness, success and whatnot are good.
None of those people have a common written book of ethics with each other, yet they can all be in agreement about basic moral values. That says morality is independent of their religions or world views.
I have respect for many people who are religious, that doesn't mean I have to respect their views on a particular subject. If they decide to raise religion as an issue, I'm going to offer rebuttals to points I am not in agreement with.
Peace and universal tolerance doesn't mean you're not allowed to debate points. In fact, open respectful debate is usually key in determining what is true. If having your opinions critiqued offends you, the only advice I can offer is to grow up. I personally enjoy having my opinions tested in a good debate, it's been very enlightening over the years.
Because getting back to your initial fallacious argument... Atheism is not a world view. The only guaranteed opinion they hold in common is that they don't believe in a god.
As Atheists, we do not have dogma, and that is what you are essentially criticizing us for... We don't have a centralized "moral authority", because it's completely irrelevant.
Furthermore, you can't comprehend the idea that people just want to be moral for the sake of being moral... and don't need big brother dictating to us on how to act.
Despite the lack of Dogma, we are all generally in agreement that we want to see the world become a better, more peaceful place. We all generally have the same moral ideals, because most people naturally want to be good people.
But what you are not recognizing, is the ideals expressed above are totally independent of atheism.
It has nothing to do with anything at all apart from an opinion on a god claim. Every other opinion a person has, may it be a moral/ethical value, or whatever is totally unrelated. This is why a centralized authority is irrelevant.
If you want to talk worldviews, then the majority of atheists would identify themselves also as secular humanists. That is a worldview, Atheism is not. Again, Atheism is a singular opinion on a single topic. If you want to read up more on Secular Humanism, here's the Wikipedia page:
Secular humanism - Wikipedia, the free encyclopedia
So I guess to finally skewer your point, Atheists are not chaotic because Atheists do have worldviews.... Atheism however is not that worldview, because it isn't a worldview. There's a number of different ones someone could choose, and I'd say out of the Atheist demographic, most would go with Secular Humanism. Chaos never enters into the picture.