I think it has to do with the business of being a film reviewer.
First and foremost, I don’t think film reviewers’ taste is always in line with the general public just do to the sheer amount of film they consume. If you’re used to eating steak tartar, McDonalds isn’t going to resonate with you.
Second, mediocre reviews don’t engender a following. Since these reviews are meant to sell papers or clicks, reviewers need a following to keep reviewing as a professional. People want “GREATEST FILM EVER!” or “I JUST WASTED TWO HOURS OF MY LIFE!”. You can see from box pull quotes how many films are rated the best in whatever genre or overall. Also, I think the really vitriol ridden bad review is where reviewers make their name in this market.
Both of these things work together to mold something that isn’t always entirely objective not always through the fault of the reviewer or the person reading the review. So like you said, it’s good to know where your own tastes lie and the reviewers that most exemplify that or just watch what you fucking like.