ISTFlyer

It's the normal procedure. The passenger should follow all crew instructions, otherwise, they could be offloaded before departure.
Indeed, that passenger should have finished his phone call when the doors are closed and switch it to airplane mode. ( US Federal Law ) The safety briefing takes around 3-4 minutes. He had 5 minutes to hang up his call and go texting instead as audio calls from the airplane Wi-Fi is not either permitted. I don't want to misjudge that passenger but probably he had money to spend on a walk-in ticket for the next flight to his final destination.