The "reddit mod" the comment you're responding to would be one in charge of a particular subreddit, not of the entire network (the latter would be an "admin" in reddit parlance).

A quick perusal of https://www.reddit.com/r/SubredditDrama/ should be sufficient to understand that subreddit mods indeed do go on power trips of capricious banning, including for the grievous sin of mentioning a competing subreddit.