In a scathing investigatory report released last week, Major League Baseball commissioner Rob Manfred repeatedly refers to the Houston Astros’ sign-stealing scheme in 2017 and 2018 as “player-driven.” Yet Manfred also declared: “I will not assess discipline against individual Astros players.”

So while Manfred suspended Houston general manager Jeff Luhnow and field manager A.J. Hinch for the 2020 season—they were later fired—no active players were even named for their involvement. Manfred justified that decision by saying...