Justaminute: What you propose does not sound unreasonable to me. When I was a non-paying member I was wondering whether I could post to discussion boards or not, before I post my first ignorant question that some very helpful paying members bothered to answer.

The creation of a board specifically for non-paying members to post and the reservation of the others for paying members would help a lot, I think.
This way, those willing to help could check that board while those like you, that are bothered by those posts could avoid the "nuisance".

I think that complaining is as much human as possible and that it is not confined to either paying or non-paying members.
It is in anyone's discretion to misinterpret a complain if they so wish, but this does not make the interpretation right.
Complaining is a form of interaction and posting a complain in a general way *may* result in the improvement of someone's situation(or it may get them flamed, of course :P).
I am one of those that prefer even flames to stay in the non-condescending spectrum of discussion :).