I've encountered this argument a few times over the year. Most recently last night in respect of Net Promotor Score (NPS) and the previous work with an NLP/Spiral Dynamics advocate. Just to be clear there is a difference, NPS has been challenged by multiple authorities but it is not a pseudo-science like NLP or a pseudo-science dressed up with fake and perverted hierarchical ideas of enlightenment like the Beck/Wilber version of Spiral Dynamics (I have more time for Cowan, but with reservation). What is interesting, when you get away from the fanatics, as I did in both conversations, is that the deficiencies are acknowledged but the argument is advanced that I find it useful or there are somethings there that work for me and variations on that theme. I've had similar discussions with some senior figures in the Agile community who do not see the point of what I call (and value) namely theory informed practice. They argue for good people doing good things that work, I argue that without sound theory you cannot reliably safely scale practice or draw conclusions as to efficacy beyond the immediate context of your perception of its action.
Another problem with it just works arguments is that you can't really justify the approach over anything else which just works. So if you are an Agile programmer arguing for a method and you don't know The Why you are no different (epistemologically speaking) from the evangelical creationist who also argues simply (in the sense of simplistic) from experience. Theory and practice need to co-evolve, something known as Praxis which has been a theme of many posts here. If it works, find out why; then you can scale. If it works and you don't know why; proceed with extreme caution and skepticism and avoid evangelical advocacy. So it's OK to say that NLP has some methods which work in specific contexts. It does, but often they are part and parcel of a body of material that has been co-opted into NLP from related fields (like mirroring) but which does not of itself validate the overall NLP 'philosophy'. Similarly the original Clare W. Graves work has utility but not if you add Integral and aspire to higher levels of status, especially when you have to claim higher and high levels of colour to maintain mastery (I think the idiots have now gone a level above Coral), personally I am Proud to be Brown.
NPS is different, its an example of something without any real foundation that becomes a norm and then has utility. That has more interest and we are developing a version of SenseMaker® that will both create an NPS output, but will also add narrative and advocacy. More on that in a future post, and it was the subject of detailed conversations over a good meal last night.