It's not hard work to join Airdrops I guess that's why many refer to them as free money, you just need to follow the project social media accounts like facebook and twitter and do some retweeting, this won't take much of your time, can't be compare to bounties that takes weeks and months
Even some airdrops take a long time to send and I have filled so many forms and applied for so many airdrops but I don't think I get all of them maybe because most of the airdrops are cancelled and some change their mind.
that is why there are so many people who cheat and an unreasonable number of participants with a not so large allocation. many have joined the airdrop campaign just to try their luck with the tokens they will get.
Most of the good and decent airdrops now do KYC for the same reason and make sure there is no way the same person can claim the airdrop multiple times. I have seen even guys submitting fake identity proof and claiming more coins so there is not much that can be done about it but at least a single guy cannot claim the airdrop 100 times because making an email and claiming is way simpler than arranging fake IDs.