And since the OP has already been answered, and the thread has long since derailed, let's expand on the obvious objection to classifying atheism as a religion generally...
It is impossible to answer the OP, without classifying Atheism as a religion. If Atheism is classified as anything OTHER than a religion, it cannot be compared with Christianity. Let us, therefore, NOT expand on your obvious objections; but rather, let us dismiss them.
Let's take all the cases that are uncontroversially regarded as religions- Buddhism, Christianity, Islam, Hinduism, Judaism, and so on, and see what they have in common. And when we look at all of these, we see precisely what I described before- not a list of features common to each and every one, but a list of overlapping similarities, some conjunction of which are common to all. Some of these features are-
-a canon
-rituals
-a god/gods
-teachings RE ethics or moral conduct
-teachings RE the origin of the universe/the world/humanity
-places of worship
-recognized authorities (priests, rabbis, Popes, saints, etc.)
-organization, whether loose or strict).
You seem to be trying to, in your own words, "derail" this discussion. In order to
compare Atheism with Christianity, you need to find elements they have IN COMMON (such as, "All are apples", or "All are oranges"), not elements in which they differ. Once having done THAT, you need to look for things in which they differ (such as, "These apples are green" VS. "These apples are red"). You seem to be trying to avoid the obvious.
Let's stop with your side-track here, and begin on the same page. If you will, I will list items that Christians and Western Atheists have in common (as though I haven't already)
- They are both convinced that they are absolutely right (This is not the case with non-Abrahamic religions, which generally give free reign to syncretism).
- They are both convinced (read "believe") that the laws of nature are ruled by their god and their god only. In the atheist case, there is no God, ipso facto, the laws of nature were spontaneously generated -- their "god" is "nothing", resembling Buddhism, perhaps, more than Christianity; but definitely a religious belief that can be compared with the Christian belief. Alternatively, their god is "Nature", Whom Christians call "God"
- Both Atheism and Christianity are strongly proselytizing, as evidenced obviously by the vehemence of the many arguments between them on the Internet
Those are salient points, which seem to be obvious to anyone but Christians and Atheists.
Now, just to let your dead dog be buried, let me deal with the points of "similarity" you brought up:
-a canon
By this, you refer to a body of literature considered "authoritative". The United States Government considers the US Constiution as "authoritative", yet it is not a religion.
-rituals
There is a ritual followed in courts, such as "All Stand", "Order in the Court", etc. The judge sits here, the jury sits there, etc. Courts, however, are not religions. Neither are children who ritually wear costumes to go "trick or treating" religious.
-a god/gods
"Gods" are "religion-defined" entities responsible for the workings of the world we know. Western Atheists do not state who their responsible entities are, so by default, those are the same as those Christians believe in. De facto, let me give them the credit of believing the universe is ruled by "nature". People of various religions consider "nature" to be a god or gods; Atheists consider this entity to be a non-god, according to their religious definition. "Gods" are therefore defined by the "religions", and "religions" are defined by their "gods". That is circular reasoning.
-teachings RE ethics or moral conduct
In any given country, essentially the same ethics and moral conduct are taught to one and all. In the United States in particular, few can afford a private education in these matters. Albert Einstein, for instance, grew up in a Catholic school, as did US President Barack Obama. They were both taught the same ethics and moral conduct, but neither of them is or was Catholic.
-teachings RE the origin of the universe/the world/humanity
Exactly the same applies here as to the previous point.
-places of worship
"Worship" is a religiously-defined term, just like "god". Atheists certainly have places where they gather together for "fellowship", just as Christians do. For those of us in the cracks between religions, like Zadoz, for instance, that place of "fellowship" is the Internet -- where Atheists also tend to fellowship. Worship originally referred primarily to animal sacrifice. Few people do that any more; and most people in the world, including "religious" people, do not gather together in any "place" for their worship: Religious "gatherings" are essentially no different from secular or atheist "gatherings".
I was part of a Jewish congregation for a year. We met in a side-room of a Catholic church. That did not make us Catholics. In my "Evangelical" days, our congregation met in a junior high school. The central places of gathering for Hindus are rivers, not buildings, which were not specially constructed for religious purposes; the Worldwide Church of God used to gather around their radio receivers, etc. In the Soviet Union, churches were converted into museums; and the only church building my wife and I regularly go to is a restaurant. An atheist revolutionary group I was part of once met in a Methodist church.
In sum, there is nothing intrinsically "religious" about the place where "religious" people meet vs. where "irreligious" people meet.
-recognized authorities (priests, rabbis, Popes, saints, etc.)
There are few places in the world, where "religious" leaders hold more sway than "secular" leaders. Meetings are meetings, groups are groups, and most of these have leaders. There is nothing "religious" or "non-religious" about having people in authority.
-organization, whether loose or strict).
Do I even have to answer this? Commensurate to their numbers and concentration, there are probably as many "atheist" societies as "religious" societies. The state I live in is overwhelmingly "theist" (in that the vast majority believe in some sort of god), and overwhelmingly "religiously unaffiliated".
The bottom line is that the points you use to define "religion" define essentially nothing.
