My guess without have to do a bunch of reading and number crunching is that vaccinated people weren’t getting earlier variants but now when faced with a variation that the vaccine is poorly matched to, they’re getting sick but less so than someone who is COVID naive. However the unvaccinated in many cases have had COVID a few times. Many of these people were hospitalized in the past. Among that population there is a lot of natural immunity built up from infections from other variants, which may provide better protection against the latest covid than vaccines. But that’s all a wild ass guess.

[edit] I really don’t get why people are so animated by some cautious speculation, that’s presented as just that but don’t have anything to say in reply.