I think it comes down to his deception of the team with the "reality show" that was later cancelled.
He had this entire reality show sold and all ready, and he dropped it on the lap of the team, giving them a major surprise AFTER they drafted him.
If he's the type of person who will surprise them with "Oh, I brought a tv crew", totally putting them on the spot... then he's the type to have other surprises eventually. It's like the player that got bullied on the Dolphins... if he's the personality to TRADE deaths threats (he was giving them too) with teammates, then go to mental hospital and get a lawyer... well, he's a loose cannon that they don't want around the team.
Personally, I thought his play WAS good enough. Not amazing, but possibly good enough. I think the Rams knew the moment the talk show was imposed on them, that 24 hours after game 4 of pre-season, no matter how he played, he was getting released.