South Africa is hardly the only country where multivitamins are common. If rationality were the only metric for decision making, I would expect homeopathy to be far less common globally than it is today.

As for Aids denialism, South Africa suffers from a case of cultural antiestablishmentism, particularly in the context of Western medicine. Thankfully our government has stepped up in recent years, and actively promotes HIV/Aids education these days.

Homeopathy is the beloved little black sheep of natural health. I would say half of natural health industry people don't believe in it, know it doesn't work, but they have to go along with it. Otherwise, to admit (as countless studies, and the federal government have done) that homeopathy is completely without merit, would threaten the entire house of cards that natural health is built upon. I remember last year when the FTC announced their enforcement action on homeopathic OTC drugs, there was an unusual silence from the natural health community. Almost a shrug. From the inside it was laughable at the lack of concern for homeopathy's future.

Climate change skepticism does not belong in the same bucket as anti-vaccination.

Why? Both beliefs are held against current scientific consensus and have only a few supporting studies, while vast majority of studies support the contrary.

You could argue that technically "climate change scepticism" only means you don't know, but in practice climate change sceptics argue for political actions (or inaction) basing on their (lack of) beliefs.

Similarly I can be anti-vacc without claiming "vaccines cause autism". just claiming "I'm not sure what they cause, so just to be sure don't do it".

The science in favor of vaccination is very straightforward and well-understood. It's easy to run double-blind tests and determine the truth of the matter.

The science in favor of anthropogenic global warming includes two parts: well-understood physics and chemistry (which is quite trustworthy and is actually science), and a bunch of conflicting computer models of a chaotic and poorly understood system with a huge number of inputs and feedback loops (which I'm not sure why anyone trusts).

This blog post puts it pretty well: http://blog.dilbert.com/post/158778029326/how-to-change-my-b...

Don't forget the natural medicine deniers over there! Just because they have a major bullshit industrie does not mean nature never made good medicine.

(I know I just went full circle)