Red pistachios don’t exist anymore – in the US anyway – because of politics.
Pistachios are native to the Middle East, and Iran used to grow about 98% of America’s supply. The traditional method of harvesting them is to cut down the grape-like bunches and store them until needed. But storing “wet” pistachios for more than 24 hours creates an unattractive (but harmless) mottling on the shell, which Middle Easterners “fixed” by staining them that unnatural shade of red.
Not surprisingly, importing Iranian pistachios was banned in 1979 due to the hostage crisis, so California farmers got into pistachios in a big way. Those farmers learned that, if you put the nuts in an industrial dryer within 24 hours of harvesting, the shells didn’t stain, so there was no need to dye them. Some did, at first, because that’s what consumers were used to. But the whole practice soon died out, so Gen Z kids don’t get the Naked Gun joke at all.