I don't believe in all of these, but I think they're interesting:
All of the significant figures of the Civil Rights Era were assassinated as a cleanup operation to move on to cults and serial killers, then religious fundamentalists, then teens. The pattern before this was with Southern revivalists, bandits, and organized criminals, in that order. This may go all the way back to Federalists versus Anti-Federalists or even Patriots versus Loyalists.
Quantum physics is developed and the ideas of alternate dimensions and time travel are propagated as a form of escapism because physics to that point indicated assured outcomes for every event, meaning determinism is correct and free will doesn't exist across time.
"Human" is an umbrella term used to describe chimeras of species of hominids. Some of these chimeras, such as the San, reached dead ends in concepts as simple as self awareness.
The prominence of cancer as a cause of death is due to both environmental pollution and the adoption of sedentary lifestyles, which themselves promote environmental pollution. The roots of cancer causing issues aren't tackled because cancer research is heavily tied to life extension research.
You could give yourself any mental illness. Many of the MK projects were meant to determine how people gained mental illnesses and what was required to induce them. People don't focus on how much worse the MK programs were in Canada after they were revealed in the US and UK.
Francis E. Dec's ramblings about gangster computer gods were banal criticisms against the US government and post-WW2 world order.
Jesus is an amalgam of figures just as Judaism is an amalgam of religions, but the god of both testaments is the same. He was an inevitable figure as Western religions pushed toward centralization, and similar figures existed beforehand but failed to gain wide audiences. Peter and Paul are two figures who were forcibly reconciled to maintain a Christian church.