To which I would say that using your camera's native aspect ratio to dictate what you shoot is bass-ackwards.
Which aspect ratio is superior? 1:1? 4:5? 2:3? 16:9? 11:51? How can you know which aspect ratio will be best when buying a camera? Wouldn't that require some psychic ability?
I would argue that the composition dictates (final) aspect ratio, not the other way around. If you're standing in front of a capture-worthy scene, figure out what the best composition is, including aspect ratio, and then use the tools you have to capture that with the least post-capture cropping possible.
So the core of the "does not crop" stance is underwritten by the idea that there is a special significance to the moment in which you committed to the picture, the moment in which the photographer's reasons for committing were realized. One could argue that this is the moment that confers meaning on a photograph. And actually this line of argument gets pretty good support in contemporary philosophy.
Another part of the stance involves the idea that the odds of finding "the picture" as a proper subset of another picture are astronomically small. Surely one would have moved an inch here or there, or more, had one known what was really there to explore within that subject space.
To those ends, one will work with the tool in hand accordingly. The exact crop that matters is the one your camera will permit with a finder mask. [And yes, you could envision a "crop" at the moment of capture as well without the aid of a finder mask, but it is harder.]
I personally would love it if my Nikon would offer a square crop mask. Some things really look good in a square. But the same could be said for any crop. The X-Pan 24x60 format looks very nice for many things. There is no limit. The real issue here is what the photographer is doing at the moment s/he commits to tripping the shutter, and that includes the "seeing it" part as well as the "knowing why" part.