You people are missing the point. I'm suggesting a
SECTION of the forums, not the whole website being 18+. I also suggested that it requires age verification meaning that it is forewarned that the section contains profanity and shouldn't be viewed by an audience under 18. If that causes any problems with the kids parents then the parent will see that the kid went into the section of the forums labeled "18+" and therefore the website isn't liable for the kid's actions whatsoever.
Also, you people act like this would be the only exposure that kids would ever have in their life to vulgar language. Everyday kids are exposed to bad language in television, movies, other video games, for crying out loud if they're on minecraft, chances are they are using the internet to go on other sites where profanity is easily exposed. So therefore, I don't see the problem with having an age-verified section of the forums made for people who are "18+"