IMHO the simple answer as usual is MONEY.

Anyone who gives free post just adds it to the cost of the item. Everyone knows this INCLUDING the customer. So the customer isn't getting a deal. In fact, just the opposite because it prevents me as a seller from combining things and reducing the postage. You can't reduce postage if it's already added into the item

How this hurts sellers ... if the customer searches by lowest price (NOT lowest + post), then we sink to the bottom since ours includes the shipping in the price. So your listing may never be seen by that customer if you have a lot of competition.

Why would eBay do this to their "best" sellers? MONEY of course. Since it benefits neither the buyer or the seller, then it must benefit eBay. And it does. We pay the commission based on the sold price NOT including the post. But if your selling price includes the post cost, then you're paying commission on the post too. Surprise, surprise. Not.

Dear eBay this is my opinion. Not fact as eBay sees it. Just one frustrated seller forced to lose my badge.

Pam