In this case, it redirects to Google’s general privacy policy that covers all their services. Anyway Google’s calculator stores a history of all the calculations you did in your account somewhere. So I guess it needs to have a policy stating what they do with that data.
I don’t know if phone call spam is only an American thing or something. In my country (and most of Europe) that stuff is effectively banned and doesn’t really happen.
Still hate getting calls though.