They cant, as outlined to me and others before at the end of a locked post by admin and Unicorn Noah.The 15% of the total supply set aside at the beginning of the process and sent to the merkle tree for distribution for the airdrop is locked away in the distributor smart contract and cannot ever be accessed or clawed back again if left unclaimed (great in some sense as it will reduce the overall supply/number of tokens in circulation and probably explains why they have an unlimited claim time).
Situations like the Dharma proposal https://gov.uniswap.org/t/proposal-excluded-proxy-contract-airdrop-phase-1/5811 being the only current exception to another airdrop that I’ve seen that a lot of the community and UNI holders say is acceptable and that they would vote for.
If voted for the tokens for this would thus be coming out of Community Funds due to the above lock preventing the original 15% being accessible to compensate those who originally missed out on the original airdrop due to their use of other named and accepted platforms, DEX aggregators and other means of calling Uniswap smart contracts.