The simple back-story on this one is that John Wall was hurt in the playoffs quite badly, and Washington Post writer Michael Lee wrote an article stating that Wall had clashed with the training staff and Doctors regarding their diagnosis.
You can read the full article HERE< and the important excerpt is below:
Wall refused to accept the initial diagnosis of a “real, real bad sprain” after X-rays immediately following the game were negative. According to a person with knowledge of the situation, Wall clashed with team medical staffers before sitting out Tuesday because he felt something more serious had caused his hand to explode. After a few days of confusion and concern, Wall got the confirmation of bone fractures that he never really wanted, leaving fans of the team with broken hearts.
You can see why Whittman would be angry and want to protect his guy, but in doing so he may have gone a bit overboard. Check out the above video featuring Whittman speaking to the media and having a little meltdown.