To be clear: the 'donor' was the EFF, and their only request was that the Bitcoins be given back to the bitcoin community. If you like, think of it as a bulk payment of transaction fees that the faucet would have paid if it had been operating over the last year instead of closed (due to lack of time for me to fight the scammers).
Because it sent tiny transaction amounts, it paid almost as much in fees as it gave out...
It seems that Gavin wanted to give out the coins someway, since the faucets are not really working any more in this era of higher transaction fees. Also, don't you also think he has more important things to do other than to dole out money? I am no expert in mining, but I feel it is generally better not to sit on some pools of money that don't belong to you, and there is confusion to whom they should rightfully belong. Therefore I accept this decision.