The most Legendary players in the game ever all had a code of ethics, I assume. In my time, Larry, Magic and Michael all talked trash, but I am sure that they never talked about someone having a condition like Charlie's.
What makes you sure of that? Between the lack of Twitter preventing their opponents from spontaneously expressing their thoughts and the stigma about "whining to teacher" and making yourself look weak and easily mentally dominated, isn't it difficult to know?
Of course it's possible that none of them ever said anything other than variations of "I am a great basketball player and you are not." And it's possible that they did make comments like the one KG made, and that they are/were all in the wrong.
But somehow I doubt that KG was all that unique. The players in the NBA make fun of one another's appearance on a regular basis-- from calling Kevin McHale Frankenstein's monster to calling Sam Cassell E.T. There are jokes about fatness, baldness, mental ability, and everything else going back and forth between teammates and opponents. Sam Cassell's appearance isn't, as far as I know, related to an illness... but he can't do anything about it, either.
Is it that much of a jump, in the heat of battle, to make fun of CV's appearance as if he's any other player? When KG is concentrating everything he has on beating the other team, mentally as well as physically, might he forget that while it's OK to make fun of 99% of player appearances, CV is in the protected class because he has a medical condition?
The comment was in phenomenally poor taste. But I have a hard time believing that it was far outside the usual standard for the situation.