That soldier is not *sitting on his chest*.
If you look, only his left leg is in a position to be sitting. The right leg cannot be seen, which tells me he was kneeling on it and THAT is what was supporting his weight.
He kept just enough on the guy to keep him down until the police arrived.
I noticed that while many people were mouthing off to the soldier, no one tried touching him.
They know better. The guy already showed he wasn’t taking any crap.
In the video, at about the 12-13 second mark, you can see the soldier deliberately and slowly get into position and he is on one knee, his right knee that is not showing from the angle the video is being shot from.
See my guess at dialogue when the wheelchair guy with the baseball bat came up...