because he probably wants to sell some asap after airdrop snapshot is taken, so he can buy more when price drops?... I think the main reason for having random time of the airdrop is so everyone cannot dump it in the same minute.
Maybe giving 1% airdrop each day would be better antidump measure, what do you think? If you get 1% airdrop every day at random time, there is no point selling

Yes, you are right. Dumping after a snapshot is the greatest problem from all airdrop currencies. I see this last year at Byteball. Your Rule with 1% every day would be a solution. No big Coin value at on time, to flood the market. This can bring a stable Price, only the Time after the last Airdrop when the Distribution Address is empty would be critical. I think at this time we see a big dump. I hope Dev Team brings some big News at this time, that any User see the Coin Worth and HODL