The thing I always love at times like these are that people forget that players are actually human beings too.
Should he have thrown the chair? Of course not. But haven't we all done things at times we've later regreted.
The problem for professional sportsmen is their screwups tend to be recorded be a dozen or so cameras, and therefore magnified 100x.
I can remember plenty of 'incidents' I provoked as a high school rugby league player (number 12 in the second row) that would have had me fined/banned had I been a 'professional' - not the least of which included popping my head out of the scrum and knocking out cold an opposing front rower to win the ball against the feed.*
Did I ever get in trouble? Nope... you learn to be 'sneaky' when there's only the ref's eyes to spot you - and not a ton of video cameras.
*Scrum: The two sets of "Forwards" (six from each team) lock together and the ball is put into the middle by the "Scrum-half" of the team that have been awarded the scrum (called the feed). In modern day rugby, the team feeding the scrum will nearly always win possession from the scrum.
- for those of you not familiar with the game