A lot of the common patterns people ping as AI (like "it's not X, it's Y"*) are marketing-speak, of which there's a lot of on the internet. It's applying existing patterns in unusual locations, ignoring the original context.

The one they're pointing out (the short punchy sentences) also apply to things like politicians and news articles. Blog posts are a bit odd.

* And here I mean those literal exact words. People are also extrapolating to similar patterns that use different or more words than "it's not" and "it's", but those flow better and aren't what I'm referring to here.