Made contact with the head. It's a high tackle. An illegal tackle. Worthy of a penalty. End of discussion.
And you f**kwits claiming he acted, you don't know shit. You can cop a massive belting to the head and walk away without a problem. You can die from a lovetap. The head is a very complicated part of the body and how heavy the blow is isn't always in direct proportion to the severity of the effect on the guy on the receiving end.
I'm a boxing fan, I've seen massive hits from blokes far stronger than you and I do absolutely nothing to the other guy, I've seen much softer hits KTFO of a fighter if it's timed well and hits him at the right angle.
None of you know if Luke acted here, he deserves the benefit of the doubt.