reddit has a system that declares mods as active and inactive (if you're a mod you can see who is active and not in the mod list), if reddit suspends the last remaining active mod on a subreddit, it sometimes will also ban the subreddit. So your subreddit can be banned for "unmoderated" just because it was a low traffic sub that didn't need moderation. No idea if this applies to the subreddit this post is about.

Also, if you're an inactive top mod, you might not be allowed to add/remove mods (not sure if this applies when there are no active mods).

Ya they'll come up with any reason they want. It's their product, they'll do what they wish.

Oh they usually have a real reason, they just don't want to say what it is because that reason is what you'd expect from