Video games are a form of media like movies and music. Sometimes I watch/listen to them for "fun" (like watching a marvel movie) sometimes I do it to feel sad (music is particularly good at this). If you want to think of video games as children's toys then the idea that they need to be fun is pretty legitimate as we don't really need toys that make kids sad. I personally think video games are an art medium which means that "fun" isn't the only legitimate goal. Personally, one of my favorite games ever was To the Moon. It was beautiful, emotionally affecting, tear-jerking, but "fun" isn't how I would describe it.
It's amazing how asking a simple question like, "we are still talking about video games right?", lead to all these comments wanting to have a discussion about gaming as an art form, most of them taking my words out of context.
So by your answer, are saying you consider Shadow of the Colossus and Breath of the Wild to be games only aimed at children??
I'm not really here to engage people in a debate about 'can video games be considered art'. At the end of the day, video games are primarily a form of entertainment. There are many more classic titles that can be considered 'artistic' games, like Okami, Bioshock, Dark Souls, Ori, even indie titles like Bastion, Undertale, Cuphead... But even if they were all made with an artistic vision, none of them forgot to achieve the primary goal of a video game, which is to be entertaining (not that everyone will enjoy certain games like Dark Souls).
Titles like 'To the Moon', slow-moving walking simulators and visual novels only meant to invoke emotional interest are a niche sect of gaming, and rightfully have their own niche corners in the Steam store where most people buy them for $5 (I bought To the Moon years ago on Steam sale and have yet to play it, but I'm sure it's great).
Death Stranding however is a game with a planet size budget and a full retail price and therefore has expectations to meet every standard of a modern big budget game, not just to indulge Kojima's whacky artistic vision while putting gamers through several hours of tedium. That's why reviewers stating outright the game is not "fun" but giving it a near perfect score, look stupid as hell. Amazing I have to point that out, but here we are.