If it ain't your computer (and if no money even changed hands), it ain't your property.
So it goes quite a bit further than “a chat channel”.
Reddit, for all its faults, goes to great lengths to give its moderators latitude and discretion to operate their communities, and only steps in as an absolute last resort.
I wonder if Stability fucked up by using a minor in this case. They seem to still view Stability in high regard, mostly it seems because they are hoping for future gain from the relationship, but I doubt they'll feel that way forever. Probably they won't feel that way for much longer given Stability's heavy handed approach. It might be a lot easier to reverse some of this once it's made obvious they took advantage of a minor.
Social media died the day that Shaquille O'Neal was no longer @THE_REAL_SHAQ.
I suppose one could go the, "SD had a minor doing the work, which they then capitalized on" route, but I find it a little uncompelling.
If SD had asked the minor to moderate the subreddit, then took it away from him afterward, that would be an issue. Doubly so if they were aware of his age. From the description that was given, none of that applied.
As it is, I see it as fixing up a parking spot for the CEO; cleaning the ground, repainting the lines, putting up a nice shiny plaque, all unasked. Then getting upset when the CEO parks in the spot and leaves garbage strewn about. It's not nice, or even fair, but it is not particularly surprising either. Hard work is rarely appreciated, even when it is actively being paid for. "Took you long enough" is a phrase I have heard thrown about on projects before. When work is unfunded? You will be lucky to get so much as a mention, let alone a head nod or thumbs up.
I just hope that he can learn from this experience and remind himself how much he is making the next time he takes up a project of this kind. There is nothing wrong with working for free, but it is crucially important to remember that the merit of working for free does not somehow entitle us to anything. It's not something that brings me any joy to say, but it is true.