[sinisterlee]

It's not, they don't pay a penny to the game developers, so they are the ones ripping the developers. Also, they have hundreds of these keys, so their losses are very low.

Ok that I didn't know.

Regardless receiving negative feedback when you are selling a working product sucks, especially when you are building a new account.
One negative feedback in the beginning reduces your chances of getting sales significantly and it takes a lot of positive feedback to get your feedback % to look good again.

The negative is temporary, after getting the refund, the feedback is changed to positive.

That is a good system for example on ebay and etsy the process is manual and the buyer has to make an effort to change the feedback, it is not automatic. Ebay can help remove negative feedback but etsy makes it very annoying.

If a seller receives negative feedback on etsy and reply publically, the buyer cannot change the feedback rating themselves.
The buyer has to contact support and request it. Such an idiotic process. Addressing a claim and "owning it" is seen positively by potential buyers so why etsy puts such a ridicolous step does not make sense. They also do not have chat support for sellers like ebay.