Initially, it was unspendable because of a quirk in the indexing. That quirk has been found, studied, named, and must now be faithfully reproduced. If I recall correctly, the current client now has special case code specifically to make those coins unspendable.
Of course, he isn't running on bitcoin, but on litecoin. Litecoin is fee to choose whatever rules they wish to follow and enforce. Litecoin is already not-bitcoin, so bitcoin's rules do not apply. Also, I suspect he is running on a testnet, perhaps even his own testnet, with his own genesis block. (Or perhaps he's the guy that has the litecoin genesis block key. It would be easy to look his name up, but it is late, and I'm lazy.)
Thanks for the info. I am confused as to why he's using talking about the Bitcoin genesis block (or at least the Bitcoin genesis timestamp message) if he's using litecoin. In any case, if the litecoin genesis block is also unspendable, the same thing applies -- you can't spend it without a hard-forking modification of the rest of the network clients' code, and also knowing the private key for the pubkey the block reward went to.