I agree that more than a few sellers engage in a bit of gamesmanship when it comes to feedback.
Playing devil’s advocate.
The argument can be made that the transaction can’t be considered complete until after the buyers provides feedback. Did you get the item? Did it arrive as promised? Was the buyer happy with the purchase? The could lead to a situation where the buyer first leaves positive feedback only to find that they buyer either wasn’t happy with the transaction in a manner that the seller could have remedied if it had known about it and/or a buyer could just be “difficult” and be expecting something that wasn’t promised and leave negative feedback.
In a way the feedback can almost be considered part of the price of the item. Sort of like COD “Cash On Delivery” only FOD “Feedback on Delivery”
Not saying that this is always the case but simply presenting a possible other side.