Michael Crabtree was still upset after the game, and that probably caused his outburst against Aqib Talib. He probably wouldn't have said the same things if he had more time to calm down and reflect. He also wouldn't have said the same things if the Raiders had won the game. However, he is right. Talib was acting very immature and childish.
Micheal Crabtree has a right to wear that chain, no matter how long he has been wearing it and no matter how much it bothers Aqib Talib. It is rude to grab something off someone else's body. Thier body does not belong to you. It is rude and disrespectful and a violation of personal space.
Although I'm not a fan of allowing players to wear chains on the field of play, Talib was totally out of line here by snatching Crabtree's jewelry. Supposedly Talib had told Crabtree not to wear the chain in front of him again, but why would Crabtree listen to the opposition? It was obviously in Talib's head, and he's lucky he didn't get flagged on the play.
Calling someone childish is pretty milk. Arguably, Talib was acting childish. That is not calling a person a name just to call them a name. It is also not bullying. Rather, it is fairly expressing an opinion about a person's behavior. The person doesn't have to like what they are called or agree with it, but it is not disrespectful.