“Way too much of Agile has been not about technology, but about people and about managing things and about getting stuff done — not necessarily getting the right stuff done.”
This is the whole point of agile: progress on iterations, inspect and adapt at the end of each iteration.
Your team might build the "wrong stuff" for an iteration, realize it (inspect), then make a course correction (adapt). If you end up delivering the "wrong stuff" is because you didn't follow this very core principle of agile.
I find it hard to believe these so called "Agile Early Evangelists" can make such a statement. Their background in lean development should have made the familiar with empirical process controls, from where lean and agile come from.
My guess the author quoted them selectively to fit the "agile sucks" narrative of the article.
Edit: expanded last 2 paragraphs.