They won't stop doing it. Most bounty hunters waste time because they're guided by greed. They will kiss ass of every shitcoin dev and later come back to tell a sob story about how they were cheated and not given a proper payment.
Devs are not saints too. They think of ways to discourage bounty hunters after they've done their job like asking for KYC before paying what they owe.
Yes asking for KYC is so dishonest and just plain wrong. I don't know what this obsession with wanting to know who everyone is, is all about but I don't like it one bit. The dev could make a pretty penny selling that info.
They have no legal obligations to you so you can do nothing since you willingly handled out your KYC info without thinking.