They're basically "free money" for not doing anything in return.
I don't see how it's free money, considering the fact that airdrop participants are asked to do certain SM tasks before they're qualified to get rewards. What about the shares and tags? What about the email request (by the way, some of the projects even end up selling these emails at dark web). It's obvious that those still indulging airdrops now are merely wasting their time. It's like getting into faucets – much noise, less reward (sometimes, no rewards at all.)
Some projects have been widely successful after an airdrop, while others have gone all the way down the drain.
I ain't sure distributing airdrops can lead to the collapse of any project because what teams distribute is an infinitesimal percentage. If anything, airdrops help spread and advertise projects.
Do you think it's a good idea to penalize airdrop hunters? Will this do more harm or good to the adoption of crypto/Blockchain tech?
I think people should even stop thinking they can make any gains from airdrops and jettison the act of getting involved in it. This way, devs and their team will learn how not to take participants for granted.