Vaccines cause autism and/or other major health issues for a significant portion of the population.
Since vaccination rates in large parts of the world are close to 90% for important vaccines you'd be seeing large numbers of cases for whatever negative effect you think they had. E.g. if vaccines actually did cause autism, in a population where 90% are vaccinated you'd surely have more than the current ~1% of autism diagnosis.

Also the Covid vaccine killing people in large numbers. When the vaccine started rolling out a colleague told me with a straight face that the covid vaccine had already killed 1/3 of the population in Bulgaria (or maybe it was another eastern European country). She absolutely 100% believed it and said the media was covering it up.

Stevie Wonder not being blind is fairly up there in "inconsequential in the grand scheme" ones.

jade helm and the underground tunnels that run between all the walmarts that are actually concentration camps for white people.

oh yeah, it was all at the direction of Obama.

IMO this was the first crack in conservative America's psyche, and caused a gap for Donald Trump to enter uncontested.

JFK was not actually killed by Lee Harvey Oswald; his head just did that on its own.