I think this is the nub of it: "the very small squeaky obnoxiously loud minority".

Most people really don't like being preached at, and the agile community is very preachy. They're also very certain that agile is best practice, while everything else is cowboy.

I'm confident at this point that a sizeable chunk of the agile mantra is pretty poor practice. TDD, for example, definitely seems worse than actually using your human intelligence to plan ahead and design.

I don't necessarily agree with this article. I think most programmers do want and benefit from some degree of collaboration on problems. Mostly at the start when they're figuring out what they should actually build. I certainly sympathise with it though. Sometimes I just wish agilists would shut up and go away.