It was hinted at earlier that it's probably mid to early twenties. Although I would hazzard a guess that it's lower than that. As I said earlier it certainly seems some people act younger than that anyway.
As far as the Linux forum goes, console gaming is (whether you like it or not) still a rather child-friendly thing to be doing. So it goes hand in hand that only some sort of animosity between users can be expected as you'd presume that your getting more kids posting.
An Open Source or Linux based area caters to a very different target audience, as you said everyone in there gets their software for free. The bragging rights of what you have done, or what you're running don't last long and are (even more) pointless (than bragging in here).
It goes without saying that a forum dedicated to a mature techno-friendly audience would be easier to moderate than a forum full of people wishing to brag that they've got to level 53 ten minutes before somebody else. That their console is slightly blacker than others... etc....