When is a user review not a review?

I find there are too many user reviews on imdb that do not consider aspects of the film or TV series but simply hate on it. No reasons are give except often "My wife didn't like it" or "I'm saving you from watching this terrible show" (always so noble of them, don't you think?).

Their negativity drags the ratings down for no legitimate reason and then these users downvote all the reviews that did like the show. Which begs the question: Why is there a downvote option?  It seems only to be abused and to normalise the negativity.

The user reviews that prompted me to ask this are under the Belgian-English 2025 TV series, "This is not a murder mystery", so delightful that I am surprised that people need to express such dislike for it.