I know a lot of flight crews and am familiar with flight protocols due to my job. I don't have much sympathy for this character. He's quoted that they were taxiing and that he stood up and talked to the captain. To do that he had to have breached cockpit security which is shut off from the rest of the cabin once they start moving onto the field. That would have meant that he got up out of his seat while the plane was on the tarmac, ignored flight crew instructions to remain seated (federal law violation #1), went to the cockpit door and somehow got the captain to open the door to deal with him (federal law violation #2) and then continued to a general asshole once he got back to his seat which made the flight crew have to continue to deal with him instead of performing their job of assuring passenger safety during take off procedures (federal law violation #3).

The flight crew did the right thing having him removed from the plane. What happened after that is another issue which I don't have an opinion about. One thing for sure is that this guy committed three federal aviation law violations before they even got off the ground. I don't want to be flying on a plane where the flight crew is being distracted from their job of flying the plane safely.