Isn't this a false dichotomy? It's just a matter of how you phrase it, no?
If the increase in seller fees is reflected in real pricepoints on eBay's market, it could work out as it really being the buyers paying the difference.
That would be true but that didn't happen. Final ebay auction values for stable items (e.g. books) did not rise by +7%. The sellers really did end up paying most of the fee increases.
Yes, some sellers tried to claw back the extra fee commission by adding extra "handling charges" to the total. That had limited effect because it made prices higher than (1) other ebay sellers that didn't add handling fees and (2) competitive Amazon Marketplace prices.
Also, Ebay lets bidders sort search results by "total price including shipping & handling" so adding handling fees just pushes your items down to the bottom of the list.
Let's say the final price is 100$ and cut is 10%, so seller gets 90$ and buyer pays 100$. You could say the buyer is paying for it since the seller was willing to sell for 90$ and the buyer had to add 10$ to get the item. Or you could say the seller pays for it, since the buyer was willing to buy for 100$ and the seller has to give up on 10$ out of those 100$.
I really don't see the difference. It seems just marketing in terms of how you phrase it. I even saw companies saying things like: seller is paying 5% and buyer 5%, which seems just a way to make it look lower for both sides.
While you are correct that one way or another the buyer will be paying more it is how you present it (buyer raises price to counteract the increase vs seller being charged more directly by the service).