I can't give a definitive answer to Fool's basic question but I will re-iterate the point made by others that not all pilots are blessed with his foresight and the ATIS is there for the benefit of all pilots.
The original e-mail asked what was the point of the warning. Presumably, if you learn from the ATIS that there is a met warning in force and you don't know about it, then you are prompted to go and find out about the detail. Why do this? Possibly only the person who made the decision will know.
But in these days of Safety Management Systems you'd better get used to "rural" oddities. Under an SMS, which all ATC units now have to have, if there is an incident and it could have been prevented by putting a message on the ATIS that a met warning was current, then that message will probably have to be included. Anyone who makes the decision to remove the warning risks being the cause of another incident.
Molly-coddling? Maybe. But it's the way that ATC now has to work.
Perhaps BRS was just ahead of the game.