did op manually copy and paste and send to all 3.1 million addresses?
I very much doubt it. Such repetitive tasks would be scripted. And it was 3,208,032 addresses by the way, but only 3,207,929 different CLAM addresses were funded. Some people apparently used the same private key for BTC, LTC, and DOGE addresses, and so their three different addresses all come out as the same CLAM address.
See x9AnPHyGwRTVtqmHfw4K3wDGAWp1FwDoTv for example. It got 3 separate 4.6 CLAM gifts, because the same private key was used on all 3 coins - all 4 of these addresses have the same private key (although I don't know what it is):
BTC: 1s9VR8ofhyTrTfRKTReckvUwQWmsBVjU4
DOGE: D61F2g5Sy7skPTr243RDAX65pYF5GFrYm6
LTC: LL66kdSdkNDX7GMaVbQwtmzF9ct3zUy3Hf
CLAM: x9AnPHyGwRTVtqmHfw4K3wDGAWp1FwDoTv