I agree that the term "airdrop" is a bit misleading. Hive was a hardfork that created a new chain where some users had their assets seized and placed in the development fund. How the fork was executed, in terms of blockchain transactions, is mostly an implementation detail.
This is not dissimilar to the Ethereum hardfork away from Ethereum Classic. A large portion of stakeholders decided they wanted to erase the assets of the DAO attacker and created a hard fork to do so.