Frankly, it reads like a venomous, unconstructive rant that cloaked itself in "personal responsibility" cheerleading.

I don't think so. It's a rant about people who don't want to do hard things. Go reread — the overall thrust is not "keep your promises," but rather "do hard things and don't complain about them." He says this pretty explicitly several times.

Sometimes people should complain when they have to do hard things.

Alan: My arbitrary function equality checker is taking a goddamn long time to write.

Barbara: That's because it's mathematically impossible.

Alan: Oh, thanks. I guess I won't put that feature in, then.