The headbutt-on-the-pitch way of doing things meant that it was done as a public gesture - Mazeratti was identified in a way that must have been felt as humiliating, at considerable personal cost to Zidane. The Samurai approach.

An approach not to be recommended - simply the equivalent of very publicly shooting one's self in the foot?

Materazzi was the one who deserved to be publicly humiliated. But by this approach he wasn't. His team won the World Cup and he was seen to play a proud part in this victory. And whatever the provocation - by publicly rising to it - a player of Zidane talents and reputation is only seen to have set a poor example and to have let his team down. End of story - it was not noble gesture - just a stupid one.