Since there have been several threads regarding this, it may indicate that there are a growing number of users that believe it could be improved. To me, that is a valid reason to revisit it and possibly consider alternative methods. If the rules are not up for discussion then how were they formed in the first place.
Since you say
I assume they were allowed to be discussed at some point in time.
My discussion thread was not created on a whim either. I have had an overwhelmingly positive experience here on HF, but the Buy/Sell procedures is the one area that has never sat well with me. Closing the thread without allowing any discussion at all is far below the attitudes that I have been accustomed to seeing here on HF. Most discussions are to work towards improving an idea or product and are open to any comment that is on topic, no matter how odd or useless an idea is. I guess the forum itself is not a valid candidate for possible improvement. I'm not saying that my way is better, but I believe it is a valid discussion. I really expected more than "NO SOUP FOR YOU!"
I will refrain from starting any more threads regarding this even if this one is locked, but my opinion will remain that there is always room for discussion regarding improvement.