"The PER sums up all a player's positive accomplishments, subtracts the negative accomplishments, and returns a per-minute rating of a player's performance."
Considering that the statistic was developed by a former ESPN employee, the Worldwide Leader should know better than this. Sure, one tweet that misuses a statistic is a minor problem, but given the number of people that follow ESPN Stats & Info's Twitter account, they have a responsibility to provide higher quality analysis than this. At a time where we are on the cusp of advanced statistics becoming accepted in the mainstream media, a big name in the world of sports needs to provide its followers with a better understanding of how these statistics work.
If you want to know more about how PER is calculated, Basketball Reference provides a good explanation:
