IMO, KYC goes against one of the core principles of crypto currencies; privacy.  Being able to be involved without prying eyes tracking and watching your every move.  I believe they started mainly with ICO’s, to an extent one could understand why ICO projects are required to do KYC but I can never understand why airdrop or bounty projects will require KYC.  When I see such setup, I automatically get very suspicious of the project, they are either data farming or something else untoward.