Once a ticket is purchased, the airline has made a commitment to get someone to the destination. Since the man didn’t physically threaten Ivanka, he was just an a$$, they removed him from the flight Ivanka was on, and put him on a different flight. He may have been late getting where he was going, but that wasn’t the airline’s fault, he did it to himself.
Maybe things have changed. In the ‘80s I was flying from San Diego to Seattle and was being harassed by a guy who wanted to sit in my aisle seat. He had the middle I’d bought and paid for my aisle seat months ahead of time and wasn’t going to give it up. This was before takeoff.
He was so verbally abusive that the attendants called for someone from the cockpit, who showed up with handcuffs. He had a choice to promise to shut up for the duration of the flight or be removed by some officials and be banned from the airline.
He did shut up and take his middle seat and the flight took off. Then he began to spread his legs into my leg space and continue to irritate. The attendants moved him to another seat finally. Not sure what happened after that.