Lin, you miss the point.

I build a computer.
I get Windows.
I install Windows.

I build a new computer.
I uninstall Windows off the old one.
I put it on the new one.

I am still only using one Windows. How is that stealing anything?

It is a definitional trick by Microsnot to say that the licence is limited to the first computer only. There is no option to have a licence without this definitional trick in (save at exhorbitant cost). That is an abuse of a dominant position.