Given that the phrase doesn't appear anywhere in Frank Herbert's novels (the horrible dumpster fires by his son may have it, but I couldn't say), it's certainly a Lynch reference.

But my question wasn't what "spice" means, I assumed everyone on Hacker News knows that.

I was asking why Saudi spice is particularly relevant to US interests, when we're a net exporter of said spice.

It was admittedly a bit tongue in cheek; dramatically reduced Saudi supplies would impact energy markets in a bunch of second and third order ways we might not like.

But that doesn't mean we have to keep selling them guns.