It is always the case that this perennial topic gets confused with a variety of spurious normative claims, to the effect that one should compose in the camera and never crop. Impossible to defend. But what is usually overlooked are the reasons why composing in camera at the time of capture has a special status.
In philosophy of action, the agent commits an act, where the act is explained by reasons (beliefs and desires) which are brought to bear on the moment (and at no other time), and the meaning of the act is fixed in an important sense. Leading up to the act, the agent committed his/herself to all manner of choices, including where to stand, where to look, and exactly when to trip the shutter and commit to the capture.
In the cases where the agent is most engaged, engaged in what Dewey called "experience par excellence", we expect the agent's actions to be most meaningful in the aesthetic sense (even in the everyday aesthetic sense). In these cases, what the photographer produced at the moment of capture bears the marks of inspiration, rich inspiration, to the extent that it would be difficult for the photographer to reconstruct his/her own motivations -- or to improve upon them -- after the fact.
While cropping is not inherently wrong, there are some deficits that one has to accept in the trade. The question is often this: Is a proper subset of the frame captured an /ideal/ capture? The answer is that there is no a priori reason to believe that the ideal capture is a proper subset of the original capture. Given a rejection of the original capture, the ideal capture might have been in an entirely different angle, viewpoint, or perspective. One can only make a compromise.
Is there a normative claim in this? No. You can make your art by whatever means, with the only qualification being that it is artistically justified. But for those who are engaged with their subjects in just the appropriate way, the unedited capture will exhibit artistic depth in a special way.
For my part of it, I affirm this approach, and will only see the benefits of cropping about once in a thousand captures. But I acknowledge that other artistic approaches have merit.