What element of the blog post are you referring to? NANOG often speaks in jargon and obtuse-professional speak, but with large routing leaks there are always strong opinions expressed. It's been this way going back well over a decade.
Another counterexample: go search the NANOG archives for opinions on AWS, EC2, and SES. You won't find much reciprocal respect - you'll find a bunch of unabashed criticism on how AWS operates, and how that affects the internet.
This is a clash of cultures. Cloudflare knows their customers expect a fast, accurate, transparent explanation. NANOG participants are used to an environment where their dirty laundry isn't aired in public to the point where they get calls from reporters asking about it.
Cloudflare is walking a tight line where they're trying to accurately explain to a lay audience what happened to their customers. They can't assume their audience knows what AS 701 is, or BCP 38, or the DFZ, or the prior harm that BGP optimizers have been known to cause.
A "professional" NANOG thread would touch on all of that, it just wouldn't be pieced together under a single byline for a mass audience.