The key point is highlighted in red, "OEM license also has another variant", in what I quoted.
That is the variant that is not locked to a MB. How is it possible to lock to a MB for consumer version? Maybe the license states that it should be "locked", a form of restriction only, but actual implementation may not be possible.
If you ever tried to install windows from a recovery CD on another computer, during the installation, it will prompt "Windows cannot be installed on this computer" or something to that effect. That is what I meant by MB lock. And that, is pre-binded BEFORE purchase of computers like Dell or Acer. There could be additional script or such on the CD, but the purpose is the same, locking the copy of windows to specific hardware.
But if you use an OEM copy bought from the stores, there is no such message as it doesn't check the hardware during install. That is what I meant by "no MB lock".
Note that all these are before activation.