That doesn't really surprise me. Also, there are conspiracy theories that exist primarily in the African American community...I posted about a couple recently; the phony "the CIA is importing crack to destroy Black communities"
Jim--I see you point, but then I would think your test would also dismiss the theory that the US Public Health Service was deliberately not treating black people who had syphilis, giving them no drugs when they cam in for treatment, to see what happens. Face it, all it takes is for one conspiracy (the more outlandish the better) to be shown to be true, for the rest to be believed (or at least wondered about).
Indeed, as history has shown, people are capable of doing almost anything, and often can keep it quiet as well.
Again, I don't dismiss your test as worthless--we can't be like Don Quixote claiming every windmill is a giant, but our skepticism has to allow that they might be giants, because once in a while they are.
As for your point about Simpson, is it beyond credibility that a few sought to frame him by planting evidence (even if he was guilty)? Face it, we saw the same with nonprofessionals in the Klaus von Bulow case, and given the tendency for the blue line to cover up for brother police officers, it honestly would not have surprised me at the time if the two detectives planted some evidence to seal his conviction. I'm not saying it happened, but it's not impossible either.