Well, everyone using web apps don't seem to mind having their life exposed to the whole internet.
Windows and OEM software/drivers are on the local machine.
In a restaurant, I expect other people to see what I eat. In my own house, I don't.
In any case, IMHO the stronger argument is that just because webapps spy on you doesn't give Windows any right to do the same. Unfortunately, a lot of web companies have shown that people will throw money at you if you attract enough users, and sell their eyeballs or habits.