The Jews under Nazi rule probably had all the marks of conspiracy theorists.
No, see, a conspiracy theorist believes in something that's not happening. If you, for example, are in the hospital because a black helicopter intentionally landed on you, it's not a conspiracy theory that a black helicopter is out to get you. If you sit alone in your room every night with all your shades drawn because you are afraid of black helicopters, you are probably a conspiracy theory believer (and indeed, probably psychotic.)
The black slaves of the American South.
Black slaves were actually slaves. That was not a conspiracy theory.
Gay men in the 1950's were regularly imprisoned for being gay. That's not a conspiracy theory.
Women in Muslim countries.
Women in Muslim countries are regularly imprisoned (and even killed) for having sex outside marriage, for showing their faces etc. That's not a conspiracy theory.
Here are some example of REAL conspiracy theories:
That white Christian men are just like the black slaves of the historical American South because the evil liberals hate them and plot to keep them down.
That 9/11 was caused by US missiles carrying hologram generators that made them look like airplanes.
That the CDC is in cahoots with the vaccine companies and wants to use them to spread autism.
That condom manufacturers want to give gay men cancer by putting carcinogens in condoms.
That the Moon landing was faked by the government.
That space aliens crashed in New Mexico and the government is covering it all up.