Suarez has said himself, he will do anything to gain an advantage, getting people sent off, harassing them, throwing ppl off their game. In football, so much of the game is about focus. Clearly Italy lost focus after that at the corner where they scored the goal. Four Uruguayan guys jumped at the same spot to head the ball in. One Italian player got crushed in between and had no chance.
Suarez is a dirty player, but maybe that's how he was brought up, scrapping and fighting. Maybe where he lives, there's a lawlessness where he can get away with things like this. And then in a split second on the world stage where he has the pressure of the whole country behind him, and he needs to win at all costs, he goes and does something stupid.
Not saying I condone it at all, or that I'm a Suarez sympathiser (I'm an evertonian after all) but that's probably what was going through his mind.
Still he needs a lengthy ban and needs some psychological help to ensure he acts professionally.