I’d suspect that using GCJ as a data source they assume that “good” = solving a given round of competition. The further you reached in rounds - the better programmer you are. Not the best measure if they really used it. Coding competitions have almost nothing in common with day to day work of software engineer.

My guess would be with a binary ruler

Do they read the article before posting about it

Productive, in the commercial sense.

knows his/her shit, delivers, is aware of the trade offs, is easy to work with.