Given the strength of feeling this case has aroused I think there is a real possibility this confession was fabricated by someone who thinks Carlo is guilty. I doubt the vast majority of such people would be so unscrupulous to invent this story, but it only takes one.
You are quite right to believe in this possibility. Any newspaper, tax office, drugs agency, immigration office or police station will tell you that there are people trying to shop other people all the time.
Your introspection may have been caused by the latest charge against the mods: "disgusting." I believe that is totally unwarranted.
For avoidance of doubt, I have myself expressed some opinions that have a bearing on moderation and I wish to clarify them.
One is that I have found some moderating "heavy handed." I stand by that. I am referring to cases such as those of Robert Jasiek and djbrown, not the present case. But I have also conceded that where a poster proves to be too high maintenance, volunteer mods can be excused for bring up the portcullis (at east if they explain why). Regrettable but understandable.
I have, along with others, mentioned the importance of freedom of speech. Robert has said he supports freedom of speech within appropriate laws. I go along with that but with extra constraints. One is that the site owner has the final say, and another is, again, that volunteer mods must have the right to put a premium on their own time and to protect themselves.
In real life, anyone has the right to shout "Fire" in a crowded theatre but if it leads to someone being trampled to death they also have "right" to be charged with manslaughter and sued. On L19, someone who shouts the equivalent of "Fire" faces no such sanction, and therefore it is right if mods expect a higher standard for the use of free speech even than in real life. That higher standard should, where appropriate, include evidence that can be easily scrutinised. That is why I objected to Kirby's initial story about sexual assault. (For this forum, quoting a link to a Korean news site is not easily accessible to most people and therefore not scrutinisable). In the present case, the post by CarloCheating offered no such evidence either and was rightly intercepted (even if it, too, eventually proves to be true). Asking the poster to provide the evidence, as uberdude did, is not censorship. Nor, even, is suggesting a rewording or a slight delay in posting - time for reflection. Editors of newspapers do this all the time with young journalists.
ubderdude's response was not just commendable but going a bit further that we can reasonably expect of a volunteer mod. Personally, were I mod, I think I might handle these evidence-light cases simply but lazily by posting a note on the forum saying something like: "We are receiving contentious posts making unsubstantiated charges. This is a reminder that such posts must be accompanied by verifiable evidence before they can be posted here." I would also like to see a requirement to shed anonymity, but it seems I'd have to be the site owner to get that through.
I hope that clarifies the message from one noisy user. To sum up, I think the cheating thread, although tumultuous, is working well
and being allowed to work well through the background work by the mods. They are also usefully

demonstrating the superiority of L19 over reddit.