This is just my personal opinion, but I'm not in favor of such a forum.
First, the scope: "Beginners" doesn't specify a technical scope, and since a large part of the members here can be considered as "beginners", it would receive 90% of the messages. In fact it would just be the new "Help > General" forum, but worse
Then what would we get in this new forum? C++ questions, mostly, but then why not posts about other languages where SFML exists? Algorithms? OpenGL? Win32? Physics engines? It would open the door to many new things -- too much.
Would it be a problem to have all this new stuff possibly posted on the SFML forum? Definitely. More work for us (reading all posts, sometimes answering, moderating). And more difficulties to find answers on a specific topic, as everything would get mixed into this generic forum. Inefficient search of existing topics, so more duplicates posted
I really want to focus on SFML here, I think we can be efficient at helping people if we keep the scope limited; I don't intend to create yet another generic game dev forum -- there are already tons of them elsewhere.
But this is just my personal thoughts.