I have been thinking the same thing. Why does every language show up in the forums, no matter what you pick. Seems like they can not even get the forums right, never mind the game!
The EN DE FR settings are for the display language of any text on these forums. They have nothing to do with the separate language specific sub-forums.
When i click on "Recent Discussions" i fully expect to see any recent discussions from any sub-forum.
I enjoy reading the German and French forums just as much as reading the English forums.
It would be cumbersome if i had to explicitly change my site-wide language settings if i just wanted to pop into the French forums to read some posts.
I like the current implementation as it gives me the top recent posts of all 3 supported languages in one list.
That's good for you but having many languages all jumbled up is very messy and I like to look at only threads that I can read not have to sift through languages that I don't understand.