WoW has never allowed profanity or masked profanity in the game. The language filter has never been an excuse to break the rules either. It exists for parents to protect kids and such from people who can’t follow rules. It does not mean you can break the rules yourself just because it exists.
Blizz has had to remind folks of that since the game released.
Mature Language Filter (aka The Profanity Filter)
This can be activated within your Interface Options: Main menu (ESC key by default) Click Interface > Social and check - Mature Language Filter.
Once enabled, all inappropriate words in our profanity database will be filtered and masked to appear as jumbled characters, such as ‘*##@&’.
Note: The filter does not excuse the language used. The filter serves as a temporary shield, to help parents of minors and others who do not wish to see it, to block it. Our policies prohibit the use of both clear and masked inappropriate language.
