You are nuts, the Off Lineman gave a quick block at the LOS and then went directly at Jewell, not head hunting but feet hunting, as he dives at his feet and tackles him. So blatantly a purposeful hold I have to think it is coached to the players to do this. Maybe a reason I wouldnt want their coaches coaching Iowa.
He did dive at his feet, but he did not grab him in any way. There is no rule against blocking low in this situation. Since he didn't grab, no holding, so the right call to not throw the flag.