Good question. I guess it is as much a personal matter as anything else. When I have asked folk the reason why they embarked on their personal MA adventures, the resounding answer to all whom I have asked was...to learn how to fight, or to learn how to defend oneself. Now, this was regardless of the "do" attached to the end of the art's name. And your reasons may be completely different from those whom I asked.
In a pragmatic sense, if one just wanted to jump into a philosophical pool and not worry about the overtures to violence that a particular martial arts system might have bubbling at its core, why not take up Asian Caligraphy or flower arrangment? This would be the philosophy and "Do" without the connection to utilitarian violence.
If you answer this honestly, I think in this case, you have it: basically, that folk want the use of a martial art with varying degress of utility (that is both with and without consideration of the philosophy behind the art). Otherwise they don't have enter into the MA arena at all.
On the other hand, I have personally waxed and waned with my time in trainging cosidering the merits of what and why I do what I do. This is despite things I find fault with and despite my personal understanding of what might prove more pragmatic.
I will even venture to guess (and my personal experience with a few MMAists bears this out...at least for me) that despite the physicalness of the endeavor, every legitimate martial artist that I have met who has had a whiff of real violence shies away from actively seeking it out. Testosterone filled youth with a dualistic idea of a fight is one thing to outgrow where the ego is concerned. Potential and completely emphatic ending of life is another.
If you read what some MMAist have to say about their training (see Dog Brothers....John Kogas linked a nice website once), you get a picture of philosophy concerning what they do. Pragmatism may shine more completely in certain venues, but doesn't necessarily mean it is outside of "DO" or that it doesn't inform the same philosophical constructs in what it attempts to do.