If I told you that the American Cancer Society said wearing pendants to protect from electromagnetic radiation was hokum, it would be case closed. But when the ADA says [low carb diets are nonsense](http://www.eatright.org/Public/content.aspx?id=10645#.UCemyU...) it's contentious.
I wonder why?
I also think you're overestimating how much hackers approve of mainstream medicine generally. There is quite a lot of bad science in the medical field generally. If we were legally allowed to build our own medical devices and mix our own drugs and practice medicine ourselves, I suspect a lot of us would be inclined to do that. The government hasn't yet made it illegal to give advice on diet and nutrition, so you see more people giving advice on diet and nutrition than you see people giving advice on, say, dealing with cancer.
Well, and if you're not allowed to, some people just do it anyway.