When I go to Facebook in a browser, it shows 4 messages, but “view as desktop”

Since when does Facebook lie about notifications in order to encourage a behavior of downloading messenger, if people don't know about their mobile browser's "view as desktop", allegedly? I mean, it is a NEW notification indicator after all, not about a message I got a week ago and read then (that wouldn't actually notify me of anything, so the lie would be about it being a notification at all).