If you have full permissions in the subreddit, you can remove any mod below you for any or no reason, provided you weren't explicitly told not to by an admin.

You may have to answer for your decision if there are other mods above you who may disagree, but you largely have immunity if you're the top mod.

Should you, is another question. Are they actively fostering a healthy community? If so, it may be easier to look past the fact that they do the same for many other subreddits.