Seriously, I think this is the reason many - if not most - members join the site in the first place. Indeed, many will have lurked while reading the forums for some time before that, hoping to find the answer to a question or problem they wish to have answered or addressed.
It is usually only after they have joined that they grow to enjoy the sense of community and may wish to join in.
With respect, I think that people have a right to ask questions - even if some of these questions have been asked before, sometimes endlessly; new users, (and lurkers) may not necessarily know that this has already been asked. After all, this is a site dedicated to matters related to Apple and is an obvious place to come to ask questions of experienced fellow users, rather than say, a sales pitch or patter.
Likewise, I think it is bit rich not to expect youngsters to wish to join. Tech matters are part of their DNA and have been internalised by them in a way that is not the case for some older people and it is only natural that they will be interested in matters which have been raised and wish to contribute to site discussions and debates. Besides, the site allows membership to those over the age of 13.
Even as a joke, I'm not in favour of 'supervised threads' for newbies, or youngsters. I prefer a world where they are treated with respect, and it is perfectly reasonable to expect reciprocity from them. As happens anyway, if someone is poorly behaved, or insulting or offensive, they are usually called out on it, and issued with warnings or other sanctions if such behaviour persists.
Trolling is a separate issue, and, from what I can see, reporting an offending thread to a Mod seems to be the appropriate response to a troll's threads.
My tuppence worth.
Cheers
