We can revisit this, but the reasoning for it it this:
The purpose of this update is to make transactions on the RPF better for both buyers and sellers. A LOT of what we have done directly benefits the buyer, but we also have a few things that directly benefit the seller. This rule is one of them. Why do you have it? Because you, as a potential buyer already know if the seller is willing to take a lower offer or is willing to trade. Those elements are all built into the form the seller fills our when making their listing. If they are willing to take lower offers, they will check a box that says they will take lower offers and/or trade. In the past we have seen sellers be hassled by continual offers when they were unwilling to accept OBOs, so much like other info, we have added it to the listing and you know up front whether they will or not.