As long as the person isn't over sensitive or inflammatory about it, I think it's helpful for new players. It's super annoying when someone does it to people who have played forever and already know the rules (in that case if it is serious, just report them), or the trolls that ignore the rules (if they keep spamming and cursing after you've informed them of the rules, they won't stop so just report them instead of spamming "stop" a thousand times).
I don't mind them I think mods just get annoyed when they help out because they are "stealing their work" but really they just want more "nice points" I suppose.
It only really gets annoying when they act like they have the authority of a real moderator. By the way, we tend to forget- helping and moderating are two different things, the terms kinda mush into the same/similar definition in a sense around here because "helping" is half of a mod's job. Genuine or not, helping is help, and anyone can do it whether you want to call it mini-modding or being a good samaritan in the community..
Who actually cares like mini moddig can be useful but some people exaggerate. It is annoying. They can help greenies and answer peoples question but the people who start mini modding in color and doing this: "If you need help /msg hotmcboy123" or "hotmcboy123 Please stop swearing" And they report every inconvenient thing or try to report/write on staff profile for greenies who got scammed a cobblestone. Like seriously DONT. You wont get accepted with doing that anyway.