Oh there are plenty of shitty mods on certain subreddits, but the biggest issue is that often the community doesn't realize it. Some person gets banned for some stupid reason, the community doesn't know. That's one of the biggest issues with community moderation especially on Reddit: it is entirely too easy for moderators to act invisibly and absolutely no one would be any the wiser because the only person that could point out the abuse of power can no longer post.