Science is an empirical enterprise and thus it works through the examination of the material universe and all that exists within it. Through detailed observation, experimentation, debate, and tentativeness, science advances one step at a time through producing more and more detailed and accurate portrayals of what exists in the universe. And it is precisely because of the principles of peer review and the willingness to reconsider long accepted ideas that errors made in science can be corrected and new findings revealed and confirmed that overthrow long accepted theories.
The problem arises when certain people, adhering to extremist dogmas whether of religion or political ideology, find the findings of modern science in conflict with their beliefs. They could do the seemingly obvious thing of abandoning or modifying their beliefs to fit the evidence that all can see. Sadly, some do not. Instead, they make claims that oppose the scientific consensus, and then to explain why most in the scientific community do not accept these claims, they make additional claims of a conspiracy theory that seems to involve a great many people, which is itself unlikely in the extreme.
There is nothing wrong with proposing alternative hypotheses to explain phenomenon in the universe, and we must encourage this as much as possible for science to advance. But what must not be allowed is the assertion as dogma of anything that claims to be scientific but has never been tested through the long and slow process of peer review and subsequent examination by independent observers.
The arrogance of those who would deny the value of scientific processes, often by those who themselves have little understanding of how science works, just illustrates the incredible power of the Dunning–Kruger effect, as described here: http://en.wikipedia.org/wiki/Dunning%E2%80%93Kruger_effect We must understand that such is the danger of these attitudes that they should not be tolerated for long once they are fully exposed for what they really are.
Examples of a such unscientific and pseudo-scientific dogmas are Creationism, Global Warming Denialism, AIDS Denialism, and anti-Vaccinationism. Often, these stem from legitimate problems with a procedure, such as faulty vaccinations discovered to occationally cause problems in children, and are exaggerated far beyond rational bounds and turned into an absolute (“Vaccinations should no longer be given to children at all because a few became autistic a few months after their injections!”). We must remember that the ONLY way for anything to advance in science is by the accumulation of empirical data, and repeated testing through peer review. Nothing else will ever suffice, because no other method has ever been consistently shown to work at revealing facts.
Dale Husband's Intellectual Rants 