It has been said by many indie developers many times that purchasing games through key resellers is objectively more harmful for the developers than piracy entirely.
Key resellers tend to buy keys in bulk using credit cards. When the bank reports the card stolen, steam issues refunds. The developer of the game is responsible for these charge backs, not the storefront.
Basically, if you buy games from key resellers not only are you not giving developers money that they deserve, but you're literally taking it out of their pockets. Do not buy from key resellers, pirate instead.