Yes, I no longer think that "Atheism is a religion" is reasonableI'm sure that you realize that this is about nomenclature, not ontological status. I'm an agnostic atheist and humanist, and what that is doesn't depend on how one defines religion. Calling it a religion changes nothing about that set of beliefs and unbeliefs.
The purpose of prose is to communicate ideas. I have a thought in my head right now that you don't know about yet, but I want you to hold it as well for whatever purpose. If I choose my words well and you are literate in my language, that happens when I translate that idea into words, send them to you, and you render them as a thought in your head. Do these thoughts look alike? Are we thinking the same thought now? If so, I have achieved my purpose.
But to do this, the words must have limited, restricted meaning. The extension of a definition is the collection of things and types of things to which it refers. The more we can narrow that, the better success we have in sending ideas to one another using words. What you want to do is to broaden that extension, to include more kinds of things under the rubric of religion. This just makes it more difficult to know what you mean when you use the word.
Information theory concerns itself with this matter of the fidelity of the transmission of information mathematically: "Information theory is the mathematical study of the quantification, storage, and communication of information."
We have a similar problem in contract bridge, where we are trying to describe the strength and shape of our hands to our partners to decide or optimal contract or defense. The best bidding systems are the most granular, that is, the bids have the most limited and specific meanings. But we have orders of magnitude more possible hands to describe than bids and legal bidding sequences to represent them all, so each bid must describe a range of possible hands, but the fewer per bid, the better for communicating what you're looking at to your partner (and the opponents).
Likewise, ordinary language is the attempt to map a much smaller assortment of words onto a much larger assortment of possibilities to describe, and thus we must balance between giving words a range of meanings and limiting or constricting those meanings. We sould never broaden the meanings for no useful purpose.
OK. Now let's make the word hobby refer to everything (and therefore nothing). Let's let the word apply not just to the things we do but also to those we don't do, so now, when I tell you I have 347,000 hobbies, you can't tell if I have any that take my time.
Let's conflate those as well. Now ask me what I believe.
Here's a good idea. Let's give everybody the same name. Now you're Bob, and so am I. So is everybody else. "By the way, Bob called and wants you to call him back." "Bob who?" you ask. "I don't make such distinctions," I answer.
Speaking of collecting as a hobby, I have several of these assembled that might amuse some. The two best known ones come first:
Atheism is a religion like not collecting stamps is a hobby.
Atheism is a religion like bald is a hair color.
Atheism is a religion like transparent is a color.
Atheism is a religion like health is a disease state.
Atheism is a religion like death is a lifestyle.
Atheism is a religion like nonsmoking is a habit.
Atheism is a religion like fasting is a menu entree.
Atheism is a religion like unemployment is a career choice.
Atheism is a religion like nudity is a fashion style.
Atheism is a religion like abstinence is a sexual position.
Atheism is a religion like off is a radio station and silence a song playing on it.
However I do maintain that it is a religious position
See this post