Oh noes. What if Arbeloa stoops all the way onto the ground and somebody kicks him while going for a ball on the ground?
Intent does matter. If you play in the "spirit" of the game - ie not intending to foul or injure people - you should only be sent off in exceptional circumstances.
Intent does NOT matter, thats simply fact, you can be done for intent even if you don't make contact, and you can be done for contact with zero intent, there is no one rule, and there are rules that cover intent, and no intent.
As for the ridiculous notion that if he'd stooped all the way to the ground, its very simple, Arbeloa would have been in the wrong.
As a footballer you can expect a head to not be below waist height, exactly as you can expect that if you jump and raise your foot very high, you might make contact with someones head. This is simple common sense, its the very reason tackles are permitted and a high foot is frequently punished.
Here in covers your "in the spirit of the game", you can expect a tackle above chest height to be potentially very dangerous, so you don't tackle that high... and he did, its something you're not allowed to do, but he coupled high, with studs, being off the ground, out of control, moving fast, lots of momentum and recklessness.
How many times do you see someone jump a little with their leg out but their knee bent, with no chance of smashing into someone with their studs and no real danger, what Nani did was a kungfu kick, not aimed at anyone, but still a flying kick, and someone WAS there, and he made contact and it was incredibly dangerous. Controlling the ball is fine, leg a little high is fine, speed is fine, all of them together can be reckless and that tackle was without question reckless.