[happytoexplain]

It's not a zeitgeist, it's a common English sentence structure.

The em-dash observation makes sense. Obviously a minority of people reach for an actual em-dash. The "it's not X, it's Y" complaint is totally bonkers. We might as well call proper spelling a "sign of AI". I.e. yes, AI does it more than humans, but not by so much that it makes sense to be suspicious when you see it.

[toraway]

No one actually used that as a red flag except the OP themselves facetiously so that’s a bad example.

The AI version of what they wrote would be more like:

  People have the wrong idea about who is getting fired. It’s not John Ive. It’s Jan ordering coffee.