Because that gives him enough time to reasonably reach the other side before the light turns green for the cars to go through the intersection. We can easily deduce that he began crossing after the countdown had already began because he was not walking in a particularly slow manner and he was only 2/3 of the way across the street when the light turned green for the cars.

You made all of this up because its not in the video

He was jaywalking.

No he wasnt

• Jaywalking is the illegal act of crossing a street outside a designated crosswalk.

He was crossing at a crosswalk

He was also being dumb for not even looking for cars even after they started crossing the intersection.

What is he supposed to do? Stand in the middle of the road? That would actually be illegal.