I have nothing wrong with what Fischer said. I think there certainly is still questions about Pierce's involvement here, but in general, I don't think that the player rep should contest everything just for the sake of it.
If Pierce did make a gang sign, then the fine is absolutely waranted, and I would expect the player rep to have no problem with it. By players doing things to paint themselves as "gangsters", it looks badly on all of the players. These are the types of things that end up hurting the marketability of the NBA players in general. The more people start thinking of them as "Thugs" and "Gangsters" (and yes, I know it is complete BS, but there are a LOT of people who do think of many NBA players that way), the less chance these players have to make more money outside the game.
The Stevenson issue is even more clear. There was no misunderstanding what he was doing. And the end result is the same.
As a player rep, Fisher's job is to look out for ALL of the players. When one or two of them make the rest of the players look bad, then he should not be standing up for those players.
edit: and just to be clear, I don't believe Pierce was in fact making gang signs...and I hope that will all be cleared up.