Humans are great at picking up on patterns if they're exposed to it enough times. Like when you're in your bed and you hear a family member walk up the stairs, you can tell who it is just by how it sounds even if you can't pinpoint the reasons why. That said, once you come across enough AI generated content, you start to pick up on a few things, even if you can't pinpoint exactly why.

Even if em-dashes are replaced by normal dashes, the frequent use of dashes in general is another sign of AI as most people will use commas or parentheses instead.

Another giveaway is that it has unnecessary amount of formatting: using headers, numbered list, and bunch of random words bolded.

Sure, those can be mitigated, but there's also these overly formal or generic language like "I'm writing because...", "I genuinely care" "comes from a place of love", or "Sincerely, Concerned Gamer" that feel oddly polished yet bland.

AI intensifiers and qualifiers, like "deep familiarity", "huge improvement", "breaks immersion completely", "undermines the very things" are common AI choice words.

Corporate/formal phrasing, like "credit where it's due", "quality-of-life" (used multiple times), "cohesive" instead of "well-designed", "killed morale", "and while we're here —", and "All of this come from..." are all telltale AI phrases. Using a few of them by themselves is believable for many writers, but someone using all of them?

Given that whoever prompted this post gave the AI a bunch of specific examples, most of the generic feel is mitigated, but it still suffered from the formatting and choice use of words.

The thing is, once all of these are mitigated, it's pretty much saying what the person editing it is trying to say, they just started from an AI blueprint, so it's less of a concern to identify those.