On Moyers and Company, historian and author Thomas Cahill said something that applies strongly to many of us here. I'll paraphrase him this way: I think that all partisanship and sectionalism is stupid. I don't think there really is anything to fight about. People should just stop it.
Look at the Agile / Lean / Kanban / Add Your Own Brand Here world. It's all partisanship, all sectionalism. Perfectly compatible ideas are sold as if they are in competition: Scrum vs XP; Kanban vs Lean; Agile vs Kanban. And so on. People should just stop it.
It's all about selling
Most of this partisanship is pure sales and marketing. A big part of selling your product or services is name recognition. You have to get your name out there. And it's easier to sell something that sounds like a product than it is to sell "Jack Brown", and far easier than selling Jack Brown Consulting's Random Guy We'll Send In.
Jack hears from some word-slurring guy in a bar that Agile sounds lax and undisciplined. Jack sees his opportunity! "You want the benefits of Agile, but worried about programmers kicking back? You need Strict Agile, and you can only get it here! Let one of our trained and certified Agile Disciplinarians help you!"
Voila, a brand is born.
To make his brand work, Jack has to add in something that looks Strict and Disciplined. Whatever he adds is quite likely to unbalance the teams that have Jack's Strict Agile inflicted on them, because he has added something that didn't need to be added.
Jack, with the best of will, has now fragmented the market. He has confused it, to everyone's detriment. Once people buy into Strict Agile, they feel that they can't look elsewhere for ideas. Jack may even have warned them explicitly against this, since he wants to lock in his market, but even if he hasn't, people's natural tendency having bought a product is to resist the benefits of products they see as competing.
Even good ideas are used to divide
The same thing happens with perfectly good ideas that really can be beneficial in to a team's improvement efforts. It really is a good idea to observe flow, or to limit work in process. Unfortunately, rather than step up to the existing market and say "Here's something useful to add to your existing Scrum/Agile/Whateve practice", they create a new thing. Again the market is fragmented and people wind up using fewer good ideas rather than more.
It's not going to change
Unfortunately for the people who need help, these divisive tactics work well enough that they're not going to go away. We'll continue to see perfectly compatible ideas sold against one another instead of as complements and valuable additions.
Don't be fooled -- these ideas do work together
If you're only buying one car, you can't get both a Ford and a Chevy. But when you're improving your software process, you can -- and should -- get good ideas from all sources. Most of them are perfectly compatible and it'll be quite clear to you which few are not.
Don't buy a brand. Seek out good ideas, and apply them to your situation.