The Red Card Rule and Luke Shaw's Injury

Following the lack of call on Moreno after the horrific injury to Luke Shaw, I've seen a lot of "but he got the ball" in defense of the play. I thought it might be useful to discuss the actual rule and how it should have been applied.

Apologies for the story, but my personal experience with the rule is I think relevant here. During an NCAA game when I was playing goalkeeper, the opposition center mid made an excellent through pass to his striker towards the top of the box. I came off the line, each of us charging toward the ball, and we met at 17 yards just as he was taking a one touch shot. In order, I slid with my chest in front of the ball and player, stopped the shot and took out the striker. His plant leg was shattered. As I stood to celebrate the stop, the ref showed me straight red and awarded a penalty.

The conversation went like this:

Me: What!? I got the ball before the man. I got ball! I was playing the ball, and he was in MY box! Where was my intent!?
Ref: Get off the field. I don't give a shit about the ball or your intent. You made a dangerous play, and you've ruined someones career. This is a safety rule. You were unsafe, you broke his fucking leg. Get the fuck off my field.

As I recall, there may have been more swearing than that, but you get the idea. And that ref was right. The rule is a safety rule, first and foremost. And there is nothing in the rule about getting the ball first, it is all about protecting the player. In fact, the rule assumes that the dangerous player is playing the ball:

"Playing in a dangerous manner is defined as any action that, while trying to play the ball, threatens injury to someone (including the player himself). It is committed with an opponent nearby and prevents the opponent from playing the ball for fear of injury . . . If the action is made with obvious risk of injury, the referee should caution the player. If a player denies an obvious goalscoring opportunity by playing in a dangerous manner, the referee should send off the player." (See FIFA Interpretation of Law 12 on Fouls and Misconduct.)

TL;DR Moreno should have been booked, regardless of the fact that he got the ball with one foot. Because it was a clearly dangerous play, denying a goalscoring opportunity in the box, it should have been a red card plus penalty.