The no-true-scotsman fallacy implies a shifting or pedantically narrow definition. That's not applicable here.

Paleo fans are very clear that they're trying to emulate pre-agricultural diets. That's the sine qua non of the Paleo fad. So it's totally legitimate that they would object to evidence about agricultural societies.

Not at all. The point OP was making is that these 3 cultures are decidedly NOT paleolithic, and it's disingenuous to use them as examples of the effects of the paleolithic diet on cardiovascular health.