I agree. It's one thing to order resin items from a catalog or a web site and expect a delay, but eBay is for immediate shipment, IMHO. If there is a photo of an item for auction, it's natural for the buyers to assume it exists and is ready to ship.
I've also seen model vendors doing preorders on ebay, which is a bit strange, IMHO. But at least they are calling them out as preorders, so it's not deceptive.