I'm not sure what sentence fragments you're referring to (I didn't see any in the initial pass) but em dashes have been characteristic of Derek's work since we'll before the commercialization of LLMs
Fun fact, there are actually multiple people with the first name Derek. I post under my real name, so if you want to confirm I'm not Derek Thompson (or Derek Jeter for that matter), you can look me up on LinkedIn or the WhitePages. I'm the only Derek Tank out there
https://www.theatlantic.com/newsletters/archive/2022/10/job-...