And Green Book is not a good movie. But it's not even close to the worst winner.
Out of Africa, Driving Miss Daisy, Forrest Gump, Crash, The Shape of Water. And that doesn't include ones I haven't seen, like Going My Way over Double Indemnity.
The worst Oscar "travesties" have to include a worthy loser. The Social Network, Brokeback Mountain (although I'd disagree on that one), Saving Private Ryan, L.A. Confidential, Fargo, Pulp Fiction, Goodfellas, Do the Right Thing, Raging Bull, Apocalypse Now, Network/Taxi Driver, Double Indemnity, Citizen Kane.
The only nominee I liked was The Favourite, but this was Roma's snub, and Roma ain't Apocalypse Now. When bad movies like The Shape of Water and Green Book win in down years, who cares?