I agree with your opinion that there are many Airdop campaigns whose purpose is to get information from people. To avoid leaking personal information, you must select good project management teams. My experience is to select reputable bounty and airdrop management groups on this bitcointalk forum as Bounty Detective. I earn some money doing campaigns from this group. I hope there are many reputable airdrop project management groups on this forum to contribute to creating a transparent and safe cryptocurrency market for all investors.
always take care of your important documents, don't let others misuse them in their interests, there are lots of airdrops out there that require to fill in personal data, even asking for an ID card or SIM and some are asking for a passport with your photo, it's very dangerous in my opinion
Sometimes, these things are just unavoidable. For instance, in the use of email addresses. It is better you use an unofficial email address for airdrop so that when you receive spams, particularly those spas that are meant to phish and steal away your personal and private info, you right not have cause to fall victim.