You misunderstand. He was convicted of copyright infringement for selling unlicensed copies of Windows. He didn't do this, as copies of Windows aren't sold; they're licensed. As the article states, he didn't sell licenses. He sold recovery media which is available for free from the Microsoft website, and from OEM suppliers.

He did admit to trademark infringement by reusing the protected Dell artwork on the disks, but he wasn't convicted of that. If he was, it would have been a slap on the wrist and a fine. This was unjust and totally unreasonable.