I think the whole "rejecting narratives is a narrative in itself" isn't all that dumb, even if it sounds like a half-baked or cliff notes version of post structuralist philosophy (whose main claim to fame is the hyperlocalization of perspectives, and the application of literary critical theory to most realms of human existence). It's not that weird in that context, but if your claim is as broad and final as "not-A is the same as A, therefore it doesn't matter" , you should spend some more time developing it, not just say "it is like that coz it does" and call it a day.

The whole Deleuze thing feels again like a very simplified version of some very complicated philosophy, particularly the dichotomy "map vs territory" which cannot be distilled to just "map is when no narratives and modernity, territory is when narratives". As for who Deleuze was, he was one half of a very influential philosopher team along with Guattari, both were active members of the French Communist party (which is why it's so silly to claim to agree with them while saying liberalism is the best we have), and they are considered as some of the most influential leftist philosophers of the second half of the XX century.

It's not as stupid. The article they are talking about pertains to how the dominant viewpoint for understanding reality and the things that happen in it is narrative-based. It tries to explain its flaws and suggests alternatives. It doesn't really ask you to "reject narratives" altogether as much as to have more than one tool in your arsenal to model reality.

As for his point about modernity rejecting stories, I am not sure about that. I think he is half right that liberalism promotes decontextualising world history. But I think that linear narrative based way of understanding is very common when talking about events that happen over shorter time frames.