I call players kids all the time, but to sit here and say that it wasn't RG3's decision to play as well is ludicrous. RG clearly thought himself invincible or he wouldn't have put himself in the situation to re-aggravate or make it worse as he did. When the doctor clears you to play but tries preventative measures, it'd really your decision to go or not.
Yes, Shanahan should have pulled him, but this is professional ball and almost every single coach will do what he thinks gives his team the best chance to win(a playoff game, and a non life threatening injury at that). It's not like the medical staff stopped him.
They even said in the pregame that Andrews wanted him to wear a full knee brace, but RG3 decided he wanted the thinner sleeve instead.
Hubris caught up with both him and Shanny