For me it is that they are wrongly used in this piece. Em dashes as appositives have the feel of interruption—like this—and are to be used very sparingly. They're a big bump in the narrative's flow, and are to be used only when you
want a big bump. Otherwise appositives should be set off with commas, when the appositive is critical to the narrative, or parentheses (for when it isn't). Clause changes are similar—the em dash is the biggest interruption. Colons have a sense of finality: you were building up to this: and now it is here. Semicolons are for when you really can't break two clauses into two sentences with a full stop; a full stop is better most of the time. Like this. And so full stops should be your default clause splice when you're revising.
Having em-dashes everywhere—but each one or pair is used correctly—smacks of AI writing—AI has figured out how to use them, what they're for, and when they fit—but has not figured out how to revise text so that the overall flow of the text and overall density of them is correct—that is, low, because they're heavy emphasis—real interruptions.
(Also the quirky three-point bullet list with a three-point recitation at the end with bolded leadoffs to each bullet point and a final punchy closer sentence is totally an AI thing too.)
But, hey, I guess I fit the stereotype!—I'm in Seattle and I hate AI, too.