If they were giving away Windows for free, their behavior would still be unforgivable.
There is no scenario where any operating system including spyware or ads can ever theoretically be acceptable behavior. Any person who contributes in any way to that happening belongs in a prison cell.
If you can't support providing something for free via a mechanism that isn't pure and unadulterated evil, then don't do it for free. "We have to be monsters to make money" is not a valid position.
I understand you have qualms with Linux, and that's plenty fine, but when the large majority of servers and smartphones around the world run it, you can't say that no one uses it.