Probably because he couldn't win. If you're a public figure, it's pretty much impossible to win a defamation suit, whether or not the information is false--so I don't think that's necessarily convincing evidence that he's juicing.
What IS convincing evidence, in my mind, are the statements by just about everyone that knew Bonds personally that said he was using steroids.
If they charges against them are false, I hardly think they would just 'look the other way'. In fact, with his financial ability to fight slander or libel, I would think he would JUMP at the chance to prove that the allegations are totally bogus. With his financial security already established, I would think that his reputation is much more important to him than money.
LIES!!! ALL LIES!!!
They're jealous. Yeah, that's it, jealous. Or maybe it's because he's black. No wait, I've got it, the press is out to get him because he wouldn't kiss their butts....
The saddest part is the simple fact that he was a great ballplayer and it just wasn't enough. He threw his credibility and career away by cheating when he didn't need to.
Now only the sycophants remain in his corner (and that's pretty sad too).