The man was gnashing his teeth with malice but a lady persuades him to stop, perhaps she is his wife or sister. I see lots of people modify the video so he is thumping in time to music and the driver enjoying the outburst; they make themselves into the driver using video editing. It is a fad that is popular this month.
I myself have noticed an increase in road rage, I drive my car at the correct speed and people get angry when they're behind me, they flash their lights and shake their fists at me quite often. I'm not sure why road rage is increasing but it definitely is. I have been driving for many years and can see the difference. It is also quite common for people to drive very fast. The only time they slow down is when they see a speed camera.
What a shame.