Anger doesn't even begin to describe it

Yesterday was the day they were suppose to talk to this girl at work. They talked to her alright, and let her keep her station. They told her she has five weeks to straighten up and they spelled out exactly the way management has to act at work. I was so pissed about it. When my opinion was asked I told the store manager flat out how I felt. I told him that by letter her keep her station at work he sets the bar of professionalism so low that it doesn't mean much to be in management. Looking back I know it seems rather harsh and uncalled for, but my anger and many other feelings totally got into the way. I felt betrayed. I trusted him to be on my side here and have my back because when she isn't doing her job my job suffers. He lied to me about what he was going to do also. That just put the icing on the cake for me. I can respect anyone in management, but I cannot respect a liar. This isn't the first time they have had to speak to her about how to act, yet she still gets to keep it. I'm pretty sure if any person acted like that they would either 1) be fired 2)be demoted or 3)never get promoted in the first place. I guess I just have to deal with it...