Moderators are volunteers, just like any player, they can login and logoff. It will always be inconsistent, but using the, "Hey, he got away with it, why can't I?" argument is just silly.
How many times a day do people get away with speeding on the freeway? Yet, if a policeman pulls you over, are you going to argue with him anout how the guy passed you 10 minutes ago? If you get caught, you get caught. If it distresses you so much to get caught, then avoid doing what you got caught for.
Again, there is no argument you can put forth which makes using profanity apporpriate online.
And there is no way for us to gaurantee there will always be a moderator online. So take your chances, but when you get caught, you have no one to blame but yourself.