how was it not a penalty? Watch the reply, he pulled his shirt.
Rules of the game means a shirt pull is a free kick, it was inside the area so it was a penalty. Simple.
Yes Defoe went down, but if he didn't go down, then it would never be a penalty, you have to claim these chances when it happens.
Bingo

It also was very debatable at whether or not that counts as a foul.
How can a defender who has lost his attacker ragging his shirt about not be a foul?