Comment by whimsicalism

It saddens me a bit that this can't be distinguished by people on here. I encourage you to take a look at their profile and see if you are still as skeptical. Noticing em-dashes is facile and as you mention, common among human written text - but there are more subtle stylistic cues (although now that you mention it, this writer likely went out of their way to replace emdashes with hyphens).

I was raised in a family of professional writer-editors (but now am the tech-y black sheep) which might make the cues a bit more obvious to me. The degree to which this style of writing was common prior to 2022 is vastly overstated, the tells were actually not really that common.