Even if somebody doesnt do their homework (which OP did) a customer is well within their rights to request a refund for a defective or badly ported game shortly after buying it.
Your assertion about not getting refunds for physical games anywhere is also highly dependent on country. In a country with good customer protection such as mine I can refund physical games in a timespan of 14 days. That includes after having opened them.
their rights are determined by the service provider. you agree to the terms when you use their service.
no one can stop you from requesting a refund but they are not required to give anyone a refund.
also, there are few digital storefronts that actually allow for refunds on digital purchases. it's a shame, and will hopefully be corrected over time, but that is the current situation...