We all rarely EVEN become a murderer, and I believe if it isn't obvious that we are the murderer, it should NOT been told by a friend that has been spectating. The Innocents can win anytime, you know? How many times can you be a murderer in 10 games? Not even ONCE. We have the chat mostly so we could have fun whilst playing and not ruining the murderer's game, you DON'T know how often they become a murderer.
So do you prefer being hinted and make the murderer lose the game, whilst innocents can win almost every game if they have good spots? It's their problem if they die or not.
I agree with you though, I'm just trying to tell you that, sometimes in some games, it isn't even obvious who the murderer is. You should leave it be rather than expose them for their hard work.