Whether or not the question was one of integrity or not, it was asked in a non-offensive way. Reporters ask much worse questions all the time, and professional athletes are very used to it and know how to respond, (or how not to respond, so to speak).
The reply by LeBron was offensive, belittling, and stated in a very immature way, covering his mouth with his hand. The only reason he felt the need to reply the way he did, is because he thinks he's better than everyone else and above their criticism or scrutiny, and because he knew there was a modicum of truth to the question.
A very large number of people, especially Celtics fans, were already thinking the same thing, and would've asked the same question if they had the chance. That's why it was asked, because it was a valid point and a question that the reporters knew was on the minds of a large part of people watching. Isn't that what a good reporter's job is? To ask questions that many of the viewership is wanting answered?
I agree that she should and could have asked the question in a less abrasive way, but these guys get these kinds of questions asked them all the time, and the response was much more offensive and immature than the question was. LeBron was embarrassed by having his and his team's behinds kicked, and this was a very immature and classless way to express his frustration.
Needless to say the word "retarded" used in that context has all kinds of negative and offensive connotations attached to it regarding people who are mentally challenged, and should not be spoken or used in that manner by anyone. LeBron just showed more of his true colors to the rest of the world, and proved his immaturity to us once again.
I'm not a bit surprised, but I am a bit discouraged ... such terms should never be a part of professional sports or ever used as an insult, no matter what the provocation.