Now, if he'd implemented a mechanism to give users keys they could send him should they consent to him reading the log for moderation purposes, he would have been able to do the moderation job and not violate people's privacy. Or made structured data fields that users could consent to make public and also be used for data analysis purposes (like interests, societies, year, etc). But no. He just read their messages. He didn't even have a commercial incentive to analyse data, he just did it out of sheer voyeurism.
To make it clear: You advertised an anonymous service to a community you're a direct member of and didn't disclose your involvement in it. You not only willingly broke a moral code that you knew about, but you actually misrepresented the service in your advertisement and broke any trust you had with everyone who participated. That's a pretty serious wrong doing that warrants a little more self reflection and much more empathy towards the people you screwed over.
People running automated social networks, because there were none.
Great power comes cheaper and cheaper, no?