I don't understand reddit moderation enough to follow along completely.
You look to be the founder of the subreddit. I assume you invited and approved additional mods and they seem to have the same permissions as you do. I don't see anyone new that has been added as a mod.
What does seniority have to with it if you all have the same permissions? Are they able to override your moderator actions now and potentially boot you? Do you know the other mods? What do they have to say about this?
Basically whoever has the most seniority has complete control over the subreddit, they can remove other mods or override any lower-ranked mods decisions. That doesn't mean they would, and I trust the new top mod, but it also puts a bit of a target on their back (top mods get blamed for a lot), means they're going to be dealing with a lot of people private-messaging them instead of messaging the subreddit, etc.
Basically "ownership" of the subreddit has changed hands after 10 years to the person with second highest seniority (at 5 years).
The most senior of the remaining mods in there then became the top mod (note that it is ordered by activity in that graphic not seniority).
In what may appear to be a surprising coincidence, this is the same sub and it was three years ago that the current aggrieved mod got the top mod position by having others removed.
You look to be the founder of the subreddit. I assume you invited and approved additional mods and they seem to have the same permissions as you do. I don't see anyone new that has been added as a mod.
What does seniority have to with it if you all have the same permissions? Are they able to override your moderator actions now and potentially boot you? Do you know the other mods? What do they have to say about this?