I don't see how the game is meant for just for little kids when technically it has drinking, killing people on the street, thieving, gambling, etc. Note that the graphics make it seem less "bad", you can basically do many things that you can do in GTA. Believe me, I'm not saying that Runescape is a "bad", far far from it. I'm just saying that you could also argue that it's a game intended for adults as you could say it's for 13yr olds.
I think the moronic bunch do tend stick out more, like sore thumbs. But you can find them in every other online game too, such as WoW, Guild Wars, Everquest, you name it.
Now, Runescape sucks. Let's be honest, it sucks bad. If anything those repetitive tasks kill it with boredom more than the cretins running around typing "n00b". If it weren't for macroing, I would have quit a long time ago.