Wikipedia has 4 thumbs down 1 thumbs up and is grade B. Tor has 0 thumbs down 3 thumbs up and is grade C.
DuckDuckGo has only 1 thumbs down: "Instead of asking directly, this Service will assume your consent merely from your usage." and is grade B, presumably because of this. Startpage is grade A, has no thumbs down, but going on startpage does not prompt me to agree to anything either.
Regarding Startpage, It's not mandatory to show the cookie banner if you don't track. Startpage doesn't track you at all, so it's grade A.
Wikipedia has that all the bad things happen to your account except for the tracking, but you can still use Wikipedia without using an account. I agree that it's a B.
I'm not familiar enough with Tor to answer that grade.
Are they? The table at the bottom page doesn't explain anything - in particular doesn't give any indication why Tor might be ranked below Wikipedia (for instance). How can a service with no mentioned negative qualities have a grade C?