There is no KYC
Defi allows its users to lend and borrow from each other, without using the same procedures as traditional finance. In the absence of a central authority, KYC (Know Your Customer), credit scores, etc. are not used.
What does KYC have to do with DeFi? In principle nothing at all. You can implement KYC, credits scores etc. on DeFi systems, in some countries it is even mandatory to do so nowadays. Likewise, there are or were countries (such as Switzerland) where you could have "centralized" accounts without KYC