Having suffered at the hands of Keane when he managed Ipswich, I never thought I'd say this, but the man talks sense.
There's nothing in the rules about intent, therefore when Nani went for the ball, studs up, chest height, he was endangering the safety of the other player. The rules were applied by the letter.
"I didn't see him" is as poor an excuse as "I wasn't looking". Nani was negligent and was punished. The only season there's such a furore is that it happened at OT where referees are often scared of applying the rules.
Ferguson's behaviour was embarrassing and as for Ferdinand; his behaviour (sarcastically clapping in the referee's face) he could easily have been given a ban.
Hard luck Man U. Learn to take it on the chin, like every other club in the world, and you won't be such an embarrassment.