So much effort for so little gain... With proper preparation (i.e. a simple app ready to download everything from an account), they could have made out with the whole data of 130 accounts, silently, before tweeting the hopeless scam message. Instead, this seems like a mostly-manual effort, done in haste.
Just dumb thieves pulling off the scam of their life, or cover for a targeted attack of one or two of those 7 they actually siphoned properly? I hope US authorities will figure stuff out beyond the usual "it was a Chinese/Russian/Eastern European gang", which is just code for "fuck knows".