Actually I've been quite impressed by the level here since I turned up (from another site that practically collapsed under the weight of apathy and dull, go-nowhere questions).
(1) newbies.
Some of the best questions and discussions I've seen here (mostly in C, C++ etc forums) have been posed by self-confessed students, who have had a stab at their question, thought about it, posted code, and asked for specific help. I don't have any problems with a courteous learner.
(2) restriction to professionals
Hm, hard to define, and very hard to do (how can I give you proof my job has an IT content??). Unfortunately some people wandering around with certificates really know very little about the subject at all. And as someone else pointed out, being an expert in unix doesn't instantly make you an expert in photoshop. Many people who aren't paid a penny for their IT work nevertheless are very good at IT. Look at all the gifted amateurs who have brewed up chess programs for fun... I could learn quite a bit from any of them.
Also, lets face it, if a person can get paid well for being an expert, why on earth would they bother answering questions here? I think we have to accept that, while some people will be genuine experts writing because they're really nice people, others will be IT-knowledgeable semi-pros or amateurs filling in a spare moment over lunch. Provided the latter are friendly and don't fill the forum with junk, what's the problem?
Oh, and for interest: I am a non-computing biologist whose work nevertheless involves a lot of IT use (big data handling requirements etc), and who's written programs for data handling in the work environment, which I hope makes me a bona fide "technical user"; but virtually everything I know about computers has been from brewing up trivial games programs (etc) on the side, just for fun.
My tuppence worth: if a person is polite and asks an interesting question, I don't care who they are. If they are rude or ask something that isn't interesting to me, I just don't bother reading further...