Apparently, there are others in North America, but mostly not in the Southwest. I lived in the Pacific Northwest about a decade ago which also has a yew (Taxus brevifolia) but I don’t recall if I ever saw the berries.
That said, most folks I know were raised with a baseline of “don’t eat random berries you don’t recognize.”
Folks visiting the desert and distractedly running straight into octillos is just good entertainment. There's not much on the east coast that prepares you for a random shrub to be so hostile. Poisonous berries though, they're everywhere. I'm surprised your fellows made it to adulthood without basic suburban survival skills.
I think it's understandable. I live in a city suburb and the foliage around me is pretty much all non-toxic.
I was raised in a rural community and went camping often so we had the lessons of "don't eat random shit, you'll die" drummed into us.
Where I'm at, particularly in the suburbs, there's a distinct lack of things that are tempting to eat (like a berry) and also poisonous.