It has everything to do with the case. If not for the stock dumping, she would not have been in the position to cover it up and obstruct justice, which is what she is charged with. It was the stock dumping that she was obstructing justice about. She didn't just walk up to the DA and start lying to him about random things for no reason. Now, the whole SEC civil suit against her for stock fraud based upon her public statements being untrue is total BS, and if she fights she will likely win. Nike was recently sued for lying in public about their child labor programs in SE Asia and they were acuqitted of that, the civil case against Martha would seem to fall along similar lines.
Back to the stock dumping... a lot of people think that it is no big deal. In fact, some economists assert that insider trading is a good thing because it ensures that capital markets are more efficiently priced. What you are all forgetting however is that if people feel like the game is rigged against them, they won't invest in the capital markets and the economy will be greatly harmed.