The situation gets even worse from a diversity and internationalisation standpoint. You have to consider what different national and language groups want.
That's the opposite of "worthless".
The consequence is that you don't care about things like masses of teenage girls upvoting the latest vampire fad, people downvoting a classic because they don't understand the context or anything, because only your bubble matters to you. And if you fear that the bubble will keep you from discovering new things, there's a way to set up the algorithm to calculate your similar users so that they aren't exactly close to you - or you can go to a specific users profile if you know them and see what they're voting.
I find it amazing compared to IMDb or rottentomatoes, but for some reason I think it's mostly unknown outside of the Spanish speaking world.
There are classic, important, society-changing movies from the previous century that were highly praised by contemporary critics and won scads of awards. But then people today watch them with zero context or understanding of what was happening or what the world was like and give them bad ratings because they can only compare them to the latest shoot-em-up sequel of a sequel of a sequel.
It's one of the reasons Rotten Tomatoes is worthless for anything more than 20 years old, and why the voices of movie critics are needed so badly today.
See also: Yelp.