It's very clear that Goldman is trying to punish him for leaving, while sending a message to their other programmers that if they leave, their lives will be ruined. Even if this guy ultimately wins the state trial, he will never get back the years he has spent fighting it. Goldman has already won, and in this case that is appalling.
How is that clear? I haven't followed the case, but it seems as though he copied important intellectual property (HFT code) when he left the firm. I'm sure if a developer at Apple or Microsoft downloaded the Windows or OS X kernel code when they left that they would face charges of some kind as well.
You can certainly make the case that Goldman paid for that code, and if they didn't want it pushed upstream that's their prerogative, but it's a very different thing to sell trade secrets to a competitor (how the mass media has reported the case) and to make a backup of an open-source library you modified at work.