What has speed got to do with it? It was never a penalty in a million years. Like Swansea, or West Ham or many others in a City shirt.
Vardy has developed a way of winning penalties by initiating contact with the defender. He's not going too fast to stop him from tangling himself into the defender and throwing himself to the ground. He actually slows down to ensure the contact comes.
It's cheating, plain and simple. I hoped that the red card against West Ham would have made him re-think his approach. Clearly, it hasn't.