I agree with the spirit of your comment, but not with its wording. A game can have all the things you mention, and still feel like it's a walking simulator if you spend >50% of the time just walking, rather than interacting with any of the things that would make it not a walking simulator. When people call Death Stranding a walking simulator, they're obviously not talking about the parts where you don't walk; they're talking about the fact that, no matter what else is in the game, you sure seem to spend a lot of time just walking. And that sure sounds boring!
The right argument against that line of thought is not "there are also other things in the game." Rather, it's, "The walking itself is extremely engaging, to the extent that it has very little in common with other walking simulators and is better understood as something new."
Talk about all the systems that make the actual walking interesting, and you'll turn the haters. I was one of the (silent) people who felt like Death Stranding seemed impossibly boring, but then I realized that it's just doing what made games like Shadow of the Colossus and Breath of the Wild so much fun -- namely, traversal -- and it's trying to make this as interesting as possible through the use of many, many subsystems. Now my hype is through the roof.