It is nothing but selfishness and not caring about anyone else
Washington is a dope. Doing dope after being suspended once and letting his team down last year, is so selfish and uncaring. I am sure after last year's incident, he apologized to the team, management and players, and asked for forgiveness promising he wouldn't let them down again.
He obviously is a liar, to himself and others. How many chances do you give someone? Well, most families never give up on their children no matter how hopeless they are. The Cards are supposed to be a family. So how do they relate to this? What is fair to all? IF you really want to help him, then you let him go so he see clearly what he needs to do if he wants to have a life in the NFL. IF you are more concerned with losing him after this year and how it affects your chances at a title, then you accept him back in hopes he can give you a couple of clean years.
Personally I feel that if you really care more about him than you do the team, you cut him. Maybe he can relate to tough love. He certainly didn't relate well to the forgive and forget strategy.