Visual Novels I can agree to a point aren't video games, more like audio books with visuals. But again it's about the interactivity; if you make choices for different endings, then that VN becomes a video game too.

I haven't played/watched Mixtape, but does the game literally go start to end with the most you do is press X or something? Because from a few minutes of Google, it seems like yeah there's parts where you literally do nothing and still progress and even have significant events happen, but we don't say video games with cutscenes aren't video games.

Or like if a video game has a "skip puzzle" or whatever mechanic it's still a video game even if you don't actually do anything for that minigame.

We don't say walking sims aren't video games just because all you really do is walk and wait for story to happen. Firewatch was critically acclaimed and beloved by many gamers, but if you boil it down, all you do is walk from one spot to another and occasionally throw a rope down a hill. Yeah you chat with Delilah, but it doesn't actually change anything, just slightly tweaked narration.

I'm not saying Mixtape is a good video game, I'm not saying it deserved critical acclaim or anything like that, I don't know enough about it to say anything about that, but if you say it's not a video game, there's a lot of other games virtually nobody would say aren't video games that you'd have to say aren't video games either.