I completely agree with you, most of the airdrops have the same intention of collecting personal data through the KYC. Most of the users or newbies get attracted to the airdrops and give their data to such airdrops by expecting a reward, where they can sell that data and make money from it. So those airdrops asks for KYC never ever join them.
Some airdrops are not waste of time, some are not risky but they should be assummed risky, because, some contain links that can install malware into peoples devices, some will request for personal information that can lead to subsequent phishing attack even through impersonation in addition to email phishing. But there are still airdrops that asre legit. The way to do it is to use phones or computers that has non of your sensitive information or wallets for the airdrop.