Weird, I swear I had a recruitment email from amazon before the pandemic highlighting that this team was doing 4 day weeks with only 2 days in the office.
...but I would not be at all surprised if the requirement to be in the office was prorated too.
In other words, if you work 5 days a week (and that's probably the vast majority of employees, so generalising for an article like this is reasonable), you need to be in 3 days, but it you work 4 you might only need to be in 2.
...so I don't think the job you were approached for contradicts the position put forward in the article?