I think refs are just trained to call it if there is a question

This is right when his foot leaves the ground. At some point human beings's feet will leave the ground when falling, but there was not launching. It's not even a debate. He didn't drive the guy into the gound, but he did fall on top of him. Never knew that was a penalty

Collinsworth called it a "tackle tackle". Tirico called it a form tackle. It was just a plain old bad call.