I guess that what puts me off is the "TL;DR" expression itself. It passes a judgment both on the content ("it was too long, so I didn't read it") and the readers of the comment ("since you don't read stuff that's long, here's what it's about").

I'm certainly not criticizing hammock's summary. As these things go, his is pretty accurate. But the best you can say about a summary is that it doesn't really add anything to a discussion -- that's what makes a good summary.