I don't see it as horrible at all. Windows is owned by Microsoft, and as a profit-seeking corporation, it makes lots of sense for them to force users to watch ads while using their product. Why shouldn't they do this, especially when so many people are perfectly happy to keep buying and using Windows OS?

If you don't like having ads forced on you, then use an OS vendor that agrees with you. Thankfully, there's lots of OSes (i.e., Linux distros) that don't have any ads in them, which you can download and use for free, so this isn't really a problem.

In other words: Don't like it? Don't use it.