Because this isn't a formal environment.You make a good point. If a person can stop using that kind of language at say a job interview or at work, or any professional environment, why can't they dial it back here too?
This is meant to be fun, and censoring adults is not really fun.
I don't mind censoring in public chats in which minors are able to view/read.
But I really hope these rules apply in private messages ingame or guild chats