I went to the website the article linked to where it said that anyone could download it for free. You can't download it without the product key.

Is it overreach by Microsoft - yes. But did he download the product with his license key and distribute it?

There is a lot of closed source software that you can get for free but you aren't allowed to distribute. The first time I encountered the issue was back in 1996. I downloaded a bunch of internet tools and placed them on a public folder for customers to use of an ISP I did Mac support for (Netscape, MacTCP, etc.). I was told I couldn't do that.