No, it's not. It's a federal crime to assault a crewmember. It's a civil offence to intefere with a crewmember while they are carrying out their duties. This can be escalated to a criminal offense but this is not usual for just being difficult. Interference is usually in regards to safety.

Bumping a well behaving passenger in preference of a "more important" one doesn't really fall into either category.

Considering the passenger in this story has already consulted legal counsil, I'm thinking the lawyer agrees that he did nothing wrong.