It's all about people
Just read the article from James Shore, about The Decline and Fall of Agile.
It reminds me of a statement from a so-called programmer that:
"As every software has a bug, I'm only contributing with the entropy."
I think that's pretty obvious that even the best Practice, when executed in vain is poisonous and will, almost surely, end with bad results.
Living in a waterfallish environment for so long, helps to see it more clearly.
I had two years, good years, working with Waterfall methodologies with no issue at all.
It was 'no Agile' but we had commitment from the teams, common sense, good established design practices, short iteration burst and a strong change management discipline.
Can't say it was easy or natural as a real Agile methodology would be, but we never had a complaint or unmanageable issue.
I think that Mr. Shore is mistaken on his finger-pointing. It's not about Agile, XP, SCRUM or anything, it's all about people and what they do with the tools they've been given.