I find this interesting because most indie video game companies to do this. I have friends who make lots of android and iOS games and they ask all of their family, friends and employees to rate those games. Just so they have a chance of being featured on the App Store/ Play Store. While it may be unethical, this is rampant in the industry, and would it even be fair for a developer to be prevented from rating their own game.
Sure, they will be biased, because they have every reason to but would it be any different from movie fanboys rating their favorite movies 10/10.
Here is the link to the original email : https://i.redd.it/x9cnf7lbrvf01.jpg