When I hear discussions like this I imagine cavemen arguing about if controlling their bowel movements was healthy. The "natural" Caveman says "its a natural function and interfering with that has do be bad." He could make a good argument of it about how healthy it must be and how he gets to go whenever he wants. I for one am glad he lost that argument. Giving ourselves control over our natural functions is human and part of a disciplined, civilized, adult mind.
Also what about controlling your emotions, your inclinations (like to punch someone), sexual arousal, and others? These are all completely natural. I think there is some kind of belief that everything natural is perfect, and you shouldn't mess with perfection. But if you did let a lot of your natural things go unchecked you'd be either in a prison or a mental institute. Natural is not perfect, far from it and it is our duty in growing up to constrain our minds to benefit our lives. LDing has been a huge benefit for my life and I see it has greatly affected the lives of many others.

Don't be a caveman, let your fears go, not your bowels!
(*No disrespect meant to any real cavemen)