- Actual conspiracies and manipulation (leading to probably most imperial wars of the 20th century till today)
- A justified distrust in the government, who people identify readily as not defending their interests in the slightest
- Conspiracy theories straight up cooked up by states to misdirect, or propagated heavily from media that are either state aligned or conveniently left unsanctioned
- The manufacturing of a climate of anti-science (in the US specifically)
Are the main reasons I can identify for why it's become such a norm. When things like MK Ultra, Cointelpro, Operation Gladio...etc are all declassified, the bar gets puts pretty fucking high for what states are willing and able to do.