I find the worst people to deal with are those who have already tried Agile and love it -- without all the experience that a few dozen teams gives you. To them, as you point out, it's much more of a religious thing.

I remember my first coaching gig. I was looking to dive into a team, get into the code, make things happen! Instead, I spent the first day in what could best be called religious discussions. It was quite odd.

But in their defense, they had no context. Agile was an abstract and nebulous thing. Instead they all had heroes/demigods that they looked to for advice from on-high. The focus was on "being correct"; tool features, usage, and adoption; having a good time with the teams. All sorts of crap instead of just making stuff people want.

I see the same thing in management, with or without the Agile part added in. Once you get removed from value delivery, even if it's only just a little bit, you end up adrift at sea. So many of the management schools are just as religious as the Agile folks. They just have different demigods :)