first up, Nani didn't butt him (probably why not one single commentator or pundit said that Nani should have been punished).
secondly, you're talking about a completely different incident.
but thanks for reminding me what a dirty cunt Gallas is, I forgot he'd already had a kick at Nani earlier in the game (and, surprise surprise, gone unpunished).
Like I already said, Gallas should have got a red for deliberately kicking Nani when the ball was no where near them.
The FA are, apparently, quite shocked that the ref didn't issue a red card after the game after getting a proper look at the incident.
that's why they are considering stepping in.
The Scholes incident a few years back was a yellow card offence, which is what he received at the time.