I despise conspiracy theorists for many reasons:
1. They do not look at all the evidence, just the evidence that confirms their preconceived notions. They enter "research" with an idea up-front of whatever bigoted view it is that they want to promote, e.g. that the government is controlled by "the Jews" or "the Illuminati" or "the Masons" or "the reptilian aliens" or "the industrial-military complex" or "the pharmaceutical industry" or whatever. They only look at evidence that confirms this, and ignore the other evidence that shows government is incompetent and incapable of organising a piss-up in a brewery, never mind a huge conspiracy.
2. They diminish and belittle tragedies like HIV/AIDS, JFK, 9/11, The Holocaust, Princess Di, etc. By casting doubt on these events, they render the lives of the victims invisible on the fabric of history. It is worse than killing someone, it is utterly destroying even the memory of them. Conspiracy theorists, in my view, are worse than murderers, because they rob the victims of their only meaningful remnant: the memory of the lesson that they represent to humanity.
3. Conspiracy theorists spread views which to ignorant and stupid listeners sound plausible, and cause sociopolitical upheavals, martyrdoms, or dangerous dietary behaviours, because of lies, which the average Joe on the street is incapable of distinguishing from fact. They bluster about "them" or "they" who want to "cover up" the "truth" which the lucky conspiracy theorist just happens to "know" because some or other authority figure gave them a crackpot theory to sell. They fail to distinguish quality research from crackpottery.
4. They claim that the "official" view is "propaganda" created by "them" or "the government" or "the illuminati" or "the industrial-military complex" or "the medical fraternity" or "the reichstag arsonists" or [fill in your favourite form of big brother here]. Yet if pressed for evidence of the reasonable intent and mechanisms used by the relevant Big Brother, they are vague on details and researched evidence. Or they twist facts, or even worse, fabricate evidence. They cast doubt over things that are established facts.
5. Most importantly: They fail to ask: How is it that SO MANY people are "in" on the conspiracy and never break their oaths of silence? "Well, they're all scared that THEY will come and get them". But surely someone would be willing to be a martyr for truth and come out and tell what "really" happened? Are all those people fleeing the collapsing buildings just actors who were paid to say that passenger aeroplanes flew into them? Are ALL the scientists working on HIV/AIDS actually in the pay of a shady group of "them" whose aim is to sell ARVs to starving poor people and drug addicts? Do you really think that government is so cynical that it will kill thousands of its own people, and inflict billions of dollars of damage, just to get a pretext to go to war, when there's plenty of oil inside USA anyway? It is outrageous to suggest this. It is an affront to the memory of those who died, and the same goes for holocaust denial.
6. Conspiracy theorists take skepticism too far, to the point where they aren't even convinced when rational evidence, such as clear photos of starving people with tattoos, are presented. Rational skeptics reject theories that lack evidence: no photos, no scientific evidence. Conspiracy theorist skepticism rejects EVERYTHING as "lacking evidence" - except for their particular favourite conspiracy - and even when evidence is abundantly against them.
Explanation from Marius du Preez (paraphrase): Conspiracy theories are the same kind of thinking as religion and superstition. Because we're too ignorant to accept that there's a rational mechanistic explanation for disasters, we assume it has some "big mind" or "big force" or secret behind it, such as God or the Illuminati. Both ways of thinking are the same, and are superstitious and primitive. There is no "big plan" - either from God, or from the Illuminati, or from the Masons, or from the Jews. The "big plan" is a myth, no matter what its form. The religious and the conspiracy theorists are in effect insecure, and cannot face the fact that the world is chaotic, in the mathematical sense, and unpredictable. Such people wish to shoehorn the world into a neat mechanistic plan-based pattern, so that it all "makes sense" in the end.
--- latest debate follows ---
The neo-nazis - sorry, I mean, nazi apologisers, believe that it's a false-flag conspiracy, ie you claim that millions of your own people were killed (and provide some evidence), so you can claim a right to military action, e.g. to attack palestine and colonise it as the state of israel. Another conspiracy lunacy is the 9/11 conspiracy, also a false-flag claim: that the USA knocked over its own towers to create a justification for war against islamic states.
False flag - Wikipedia, the free encyclopedia
False flag has its origins in naval warfare where the use of a flag other than the belligerent's true battle flag as a ruse de guerre, before engaging an enemy, has long been acceptable. It is also acceptable in certain circumstances in land warfare, to deceive enemies in similar ways providing that...
I actually don't think there are any significant global conspiracies. It's just not possible to keep everyone quiet.
I think in some peoples' case, what has happened is they discovered skepticism, and applied it too strongly - to everything. So not just to God and homeopathy, but to the holocaust, 9/11, moon landings, etc. So you get a super-skeptic, who inevitably ends up being a conspiracy theorist, because he simply cannot see the difference between good evidence and bad evidence, so he assumes that all evidence is bad, and therefore, anything and everything is signs of a conspiracy.
Ivy Bedworth: Conspiracy theories can't survive in a world with google in it
Actually, Ivy Bedworth, the internet has given rise to conspiracy theories galore. The reason is the same as why christianity can survive on internet: people keep drinking the kool aid. Christians only go to christian websites, and keep drinking that kool aid. They never dare look elsewhere, and feel no need to. The same happens with conspiracy nuts. They keep going to conspiracy sites because they "tell the truth behind the lies of the government-illuminati-military-industrial-complex" or whoever is the favourite bogeyman of the day, so they also keep drinking the kool aid. A conspiracy theorist doubts everything - except his conspiracy theory. A religious person doubts everything - except his religion. A scientist doubts anything that doesn't have proper empirical evidence.