He calls Prado the worst because he swings at a lower % of pitches in the zone than most players.
So if a player takes pitches, which they often do to intentionally make the pitcher throw more pitches, he is criticized for poor decision making. That's not a real fair assessment.
Matt Carpenter takes more strikes than most, and consequently, is near the top of the list for pitches per AB, which can be very good for his club. Why call that poor judgement when it is an intentional approach? Even if you disagree with that approach, it isn't the hitter necessarily failing to recognize whether a ball or strike.
It is interesting to see Fowler as one with good recognition, yet he doesn't have a particularly low K rate.