Informed atheism is a rebellion. Not against God, for you don't rebel against things you treat as nonexistant. It's the expression of a rebellion against a popular view that it's ok to hold a belief that you can't demonstrate as true.
There's simple atheism: just failing to believe in a god for whatever reason: you've never been introduced to the concept; you're "angry" at your concept of god; you simply don't have a reason to believe. These are fine; I welcome the day when nearly everyone is a "simple atheist". These are the atheists that hardly need it as a label.
Informed atheism is a different animal: it's the statement that the existence of a god has been almost entirely excluded from belief by our knowledge. We understand there may be flaws in our knowledge, but the number of flaws necessary to allow a god to be real is staggering.
In short, a simple atheist may be easily turned into a believer - indeed, it's happened at least once to every single religious believer - but an informed atheist is an almost impenetrable nut to crack.
The simple -> informed transition is, of course, continuous. There's no overnight moment when a simple atheist becomes informed.
Does this make informed atheism a religion? It may. Many of the information entities that exclude gods from belief are necessarily theological in nature. That's not to say they all are: a discovery in science that happens to contradict a doctrinal assertion may be one entity excluding gods from belief, but that doesn't place it into the purview of theology. Instead, where the purview falls is in the theological implications of that doctrinal contradiction - so as long as those aspect are not mentioned, no scientific statement can be viewed as religious.
There's similar conceptual math that can be applied to politics - however, while there are many scientific statements with no theological impact, there can be no scientific OR religious statement without political impact, however small. Science and religion are how we describe the real world (quantitatively and qualitatively), and politics is how people operate in the real world. Every understanding in the science or religion either adjusts the estimation of the costs and benefits of policy.
The argument is easily made for science: if your expectations don't match up with reality, you're going to pay for it, and the value of scientific models is how closely they approximate reality. Religion's impact on policy is far more interesting - but one only need look at 9/11, Catholics' oppression of Africa via condom condemnation, or the political climate in the United States to see how the latter operates. What people believe informs their actions, and politics is nothing more than the actions of people.
So I've gone ahead and validated the position of religion in politics. I'm a bad atheist in that regard - but it's for a good cause. Now that we understand that religious positions have an effect on policy (and given that it's well-established that policy directly affects the welfare of people), it becomes frighteningly apparent how important is is to adjust religious views to be in line with reality as exposed by science. We need to rebel against a status quo of magical thinking counter to reality.
This doesn't have to be an all-at-once endeavor. Simple rejection of religion en masse would be neat, but it's just not what's going to happen. [https://plus.google.com/112829005077127347210](Chris Mooney), [https://plus.google.com/103773811230107801448](Sheril Kirshenbaum), and [https://plus.google.com/103377423155109727835](Shawn Lawrence Otto) understand this, and make it a point to engage the religious in discussion that may help migrate their views in the direction of reality. [https://plus.google.com/102600088268197126924](PZ Myers), [https://plus.google.com/114028411230209461552](Ed Brayton), and others considered "antagonistic" on the other hand, go with the "Praise and Condemnation" route, often attracting condemnation themselves for harsh (if accurate) rhetoric. There's also everything else in between.
In my opinion, this fanned-out approach - with some engaging the willing, while others attack the ridiculous - is likely the most effective. It's necessary to engage religious leaders and individuals. It's necessary to teach critical thinking to all people. However, there are a number of individuals that will not engage, and it is necessary to shame these people for their anti-rational ethic.
The problem I perceive in the skeptical and atheist community - at least, in the subset that is engaged in promoting rationality - is the occasional infighting over this very idea. There's a supposition that those who attack aren't helping the cause, or that those that engage are giving legitimacy to the ridiculous. PZ making fun of M & K, for example, or Mooney and Kirshenbaum spending a chapter on a book on scientific illiteracy to yell at that antagonists. I want to counter both of these:
- Those who pile shame onto the deserving - the antagonists - are creating a hostile environment for harmful unreason. That's a good thing.
- The religious are already legitimized in the public eye; there is no need to criticize the engaged for recognizing that fact or for using it to our advantage.
I'm not going to say, "we all need to calm the fuck down," since that's untrue. What we need to be doing is directing that annoyance usefully. M & K took that chapter because the radical honesty strategy employed by the new atheists (new being somehow pejorative) does result in irrational behavior and rejection from many of the hard-line religious, which is a tempting scapegoat for how difficult it is to popularize science in these populations. However, there is no evidence that the mainstream tactics used by M & K et al, in the movement to engage, are effective on the hard-liners - while there is evidence that attacks, while they intensify religious bases, do so by narrowing them.
In short, shame does convince many people out of religion - not directly, but in the effort of reactive self-education. It forces many people who are ultra-religious and would always be ultra-religious into having a fair chance at rationality.
Meanwhile, the movement to engage - derided as "accommodation" - isn't targeted towards the ultra-religious. It's targeted towards those groups that one can fairly assume are going to listen, pay attention, learn, and align their beliefs to our shared reality (regardless of what else they believe).
The issue, I think, is in whatever overlap there may be: PZ calls out a pastor that's presently helping to campaign for Science Debate, or some other such silliness. I don't think PZ should back off, or SD should drop the pastor - but I do think there are a lot of situations in which these things could be solved privately, rather than in public, embarrassing flame wars.
Or maybe they shouldn't; one of the nice things about new atheism (of which I consider the engaged to be an unwilling part) is that everything that happens is open and loud. It may become difficult to follow, but it is also often entertaining. I squee a little bit every time Abbie Smith calls Chris Mooney a name, basically because I love when she's sarcastic in general.
Overall, though, it just seems like it all takes away from the message: learn critical thinking, analyze everything you assume, and form policy based on what we can demonstrate, not on faith.