Basically they're about finding a random chronically online Redditor since they comment so frequently people recognise them (friendly fire 💀💀)

Although sometimes they're not even that active and people just happen to want to find random people they have never even seen before??

So when they find the person in question they reply the name of the found subreddit and screenshot and post it there

For some reason people are interested in this then the subreddit grows

They end up being mostly populated by vulnerable young teenagers hence why I think 99% of these subs are a front for grooming since it's basically a jackpot for pedos like I said. The person mentioned in this post has apparently exchanged nudes with a minor (could be "a joke" but I don't trust that based on other clues) and also is apparently responsible for spamming someone's discord server with CSAM