Always a good idea to cite sources so people can see the lineage of knowledge creation. To just pull it out of the Ether or mining pool or whatever is unfair. Dan Larimer whether people like him or not, has contributed more to the blockchain space technically than anyone not named Satoshi Nakamoto. This is not even debatable, as you can just look at Github, Bitcointalk, Bitsharestalk, etc.
Surprising to see this from Gavin as Gavin I thought carried himself with integrity.