All rear mudguards on MTBs are basically wrong, they look crap, get in the way and if we are honest really are just for “Altura man” commuter types.
Crud catchers, fender bender or Neo guard type guards up front make perfect sense as they keep shite out of your eyes, and seeing is more important than having a slightly cleaner back IMO.
It is entirely up to the individual if they want to leave them on year round or faff about for ten minutes every time the weather changes…
These are my beliefs on the topic, you are entitled to your own however wrong you are. That is all.