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
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.