He took a shot at KGs head while he was in the air. That's a flagrant.
Clearly you haven't read the NBA official rule book.
Page 257, Paragraph 3 and 4:
"If a player is fouled with uneccessary force or in a way which is considered dangerous, the foul will be called a flagrant, except when the player who is fouled is a member of the Boston Celtics.
Boston Celtics players do not qualify for flagrant fouls. If a Boston Celtics player is fouled in a way which is deemed flagrant, he will be charged with a technical foul or ejected, subject to the mood of the official at the time of the call."
As sad as it is this has happened before. For example, the last time they played the Nets I think Keith Bogans didn't get called for a flagrant to Barbosa yet Rondo did for something similar to Wade.
As badly as they played tonight and I will not excuse that at all, I promise someone somewhere needs to speak out about the lack of respect the Celtics seem to get from the refs.
I don't understand how a team with a top 3 pointguard (maybe the best I guess it depends on your opinion) who's actually popular and is in the top 10 in jersey sales, one of the best PF's and players to ever play the game, another HOF player, one of the most respected coaches who's praised by players retired and playing, and a team with such a storied franchise with 17 banners (the most out of any team period) can not seem to get any respect at all not even in their homecourt.