I mean it's just random people giving ratings. So the rating is about how large audience likes it, and a lot of movies are not intended for the large masses so in imdb they get a bad rating because the large mass of generic people didn't like it
It's not random people, it's people interested in cinema. Filmaffinity has a similar approach, but being more used in Latin countries, it doesn't have that US-taste pervading any review. For instance, "Perfect Days" is scored slightly higher than "Hoppeneimer" and much higher than "The Zone Of Interest", and I really agree with that.