I think Dez needed to go for several reasons, but it doesn't mean that he doesn't have a point. He's handling it poorly, but he is a mental child. If you really look at what he's saying, he isn't just making this stuff up. Someone (a player or players) still with the Cowboys TOLD him some of that stuff. I doubt he'd just make it up about Lee and Fredbeard. While it may be true or untrue, someone who isn't content is feeding him info.
It was crappy how they waited to release him. They should have done it sooner. It was even crappier that Stephen Jones called him out afterward. That being said, if he wants a job in the NFL he's doing a piss poor job of handling the situation. Even before all of this, as a gm if I needed a WR badly, I'd only offer the vet minimum for a one year deal to "kick the tires" as it were. Now I wouldn't touch him with a 10 foot pole.