1. ignorant of or uninterested in cultures, ideas, or peoples outside one’s own experience
synonyms: narrow-minded, small-minded, inward-looking, parochial, provincial, small-town, shortsighted, hidebound, blinkered.
Possible examples: Any kind of fundamentalist, the country club crowd, North Korea and Kim Jong-un, college frat houses, gated communities, the Junior League, internet RPG’s, the bookworm (of course we can insulate ourselves.) I want you to notice, insularity as a modus operandi is usually chosen by newbies.
I’ve enjoyed belonging to several of these examples of insularity.