Justify what mistake? The man won 2 rushing titles in 3 years, and was on pace to likely win another one, but for the 6 game suspension. Why would anybody think he couldn't continue to be as successful based on his past performance, age and lack of injury history.?
There was no justification involved. The Cowboys took his record and other info, and made a judgment call that it'd continue. Did it pan out? Well the contract's not done, far from it, after it does end, then you can make that judgment....