If a product is defective, broken, buggy and was sold with the deliberate concealment of these issues then I fail to see the issue with refunding, regardless of the fun you've had.
I bought a pair of new walking boots, very comfy, very nice, and not cheap, that took me on a long joyous trek. At the end however, when I took them off I noticed the heel on one of them was beginning to split and the stitching was coming loose in several places. All this after less than 10 miles. I would have been a fool not to take them back for a refund despite the pleasure they had provided over those 8 or 9 hours.
If you bought the product expecting all of the broken shit above then sure it's a bit of a cheek to then refund it, or if you bought it with the intention of refunding it later. But refunding faulty/not as advertised products is basic sales of goods and services law. You are not beholden to these companies no matter how goddamn hardcore of a gamer you are. You are a customer not their friends.