It's not an extraordinary claim, it's a mundane and plausible one. This is exactly what you get when you ask an LLM to write in a "engaging conversational" style, and skip any editing after the fact. You could never prove it but there are a LOT of tells.

"The key insight" - llms love key insights! "self-contained corruption-free" - they also love over-hypenating, as much as they love em-dashing. Both abundant here. "X like it's 2005" and also "Y like it's 2009" - what a cool casual turn of phrase, so natural! The architecture diagram is definitely unedited AI, Claude always messes up the border alignment on ascii boxes

I wouldn't mind except the end result is imprecise and sloppy, as pointed out by the GP comment. And the tone is so predictable/boring at this point, I'd MUCH rather read poorly written human output with some actual personality.