The problem is that penalties are given for any rule infringement inside the box and not for denying a clear opportunity to score. Hazard was not in a position to score there, nor was he trying to and yet it is deemed a foul and therefore a penalty.

You could be in the D with an open goal and get hacked down from behind though and nope, no penalty. That ones a free kick.

Another silly one is that a player can block a shot with their hand on the line (literally denying a goal) and it is a penalty, which the keeper can now save. This is what actually happened with Suarez in the WC. Instead of the referee being allowed to award a goal he had to give a penalty.