Sparta wasn't common like any of the contempory cities. Sparta has unique militaristic society. Hence the writer should have furnish proof within Sparta and not use proxies to generalize the same. Canada and Mexico are next to USA. The things happening in USA are hard to be extrapolated from Canada or from Mexico. You can't be reasonable to say American loves maple syrup and have cartel rampant running the drug trades simply because it is common in Canada or Mexico.