I don’t think there is an easy way to fix this. Basically it boils down to weighing the amount of legitimate purchases from these countries vs. the amount of illegitimate or resale keys bought, and then deciding which one costs the developers more money. I’m sure it fucking sucks to be from one of the countries and have to deal with this shit, but it sucks for developers who make a $60 game (that’s actually worth $60) and lose money on sales because some asshat third party key seller bought 10,000 keys at $17.49 and is reselling them for $45, making more money off of your own product than you are.
A message to people who use shady resellers: Just pirate the fucking game. You’ll hurt less people that way.