It is not free. It is traded for your identity. Maybe they want to test their KYC system, and the airdrop participants are the tester.
For some peoples it is ok to give their identity, but for some other peoples, they value their identity more than $25.
yup, for identity problems we can actually get more than that, for example if we abuse use to try lending on a financial platform and also if we can borrow it can get 100-500$ or more