Alonso didn't lose anything by trying too hard, at that stage he had in fact nothing to lose anyway.
EDIT: talking about yesterday. ^^ Fuji is your one and only valid example of Alonso throwing points away in a WDC fight (and let's not forget that in that race his car was damaged by Vettel previously). In any case, one driver related error / DNF isn't a trend, it's coincidence.
Hamilton OTOH did [many mistakes that cost him points], many times in every of his WDC fights 2007, 2008, 2010.
What you try is paint every failure to win the crown with the same brush. But that's BS, and I think you know that.
I'm not sure how hamilton's error rate went up in 2008, there was only Fuji, he was flawless in China and drove well in difficult circumstances and with very poorly set up car in Brazil. Compare that to Bahrain and Canada...
2007 the one where he felt the pressure was the start in Brazil, pressure that was experly applied and affected a rookie driver. China was down to the team leaving him out on canvas, a ferrari ended up in the same gravel trap this year on tyres that were fine.
2010 - I don't think his error in monza was down to WDC pressure, singapore was a racing incident and both times he made errors to let alonso through in korea and brazil he was struggling with the car, button was letting people through at virtually exactly the same times in both races and the cars he let by weren't alonso in a ferrari.
In summary, there might be something in it but I think his reputation as a choker is exaggerated.
Alonso, however, seems to improve when the WDC pressure is on and didn't do much wrong yesterday except lose a place at the start, he's done that a lot this year I think.