AGon staff I agree with most of your above remarks. There seem to be numerous concerns from members who feel that they should (still) be able to post feedback when in fact no transaction ever occurred; money/property did not exchange hands. Apparently the rules are being ignored, perhaps due to fb policy ignorance? That was the exact problem that I once encountered from a vindictive buyer who repeatedly tried to bully his way with me, and I finally decided to cancel the whole transaction as he kept on trying to alter the inital agreement to his further advantage. So in order to "get even" he would post negative feedback on my account, AGon staff would subsequently delete it, he would repost, on & on until his membership priviledges were called into question should the illegal behavior continue.
Feedback isn't about that; it's about whether honesty & trustworthiness in fact do exist when dealing with any particular seller.