this has become quite an interesting thread. everyone's said their bit, so i'm gonna add mine.
i think because of Lin's success, a lot of people have forgotten that he is still a person. that is, like any person on this earth, with flaws and weaknesses, and strong points to admire. so why is everyone reacting so violently when he stumbles and does something stupid and irrational?
if you claim it is because he does not show good sportsmanship, then ask yourself, have you never displayed poor sportsmanship in your entire life? i'm sure everyone's had a time where they've lost cool, whether because it was a close game, or because they were having a bad day, or because it was a game they did not want to lose. some people do it more than others, but i'm sure everyone has had a moment like that. i've broken a racquet out of anger, because i was angry at myself, during a very personal game.
i'm not using this as an excuse for his behaviour. but i'm suggesting that you can't really jump on him, when each of us has had a moment like that. if there are any shining, perfect angel players out there, well, i envy you. but as david has said, Lin has expressed a willingness to change, and i think, that is the most important thing of all. if it takes more than one incident, then so be it. i'm pretty sure we're all trying to change something ourselves. i don't see my friends dumping the world on me for a fault i'm willing to change.
for those who insist that it is no way for a world no.1 to act. well, i agree. but it's also no way for ANYONE to act, not just lin dan. so why place so much attention on him? is it because he's a role model to so many people? if so, then that's stupid. he might be a role model, but in the end, the very person you want to compare to is yourself. not to lin dan. role models are only there to guide you in your ways, not to show you exactly how to behave (e.g. i look up to lin dan, but just because he argues with his coach, doesn't mean i copy him). instead we can learn from him to not lose our temper. isn't that a good thing? to learn from your role model?
i think lin dan was wrong. but like every other person in the planet, we've all been wrong. what matters is if he changes. i don't think there's much point continuing to ponder what happened. instead, i think we should look at if lin dan gets any better (controlling his temper, i don't think he can get much better in badminton).
just my thoughts