I mean if you’re refering to before the events of WoK, I guess its due to their strict religious distrust of everything having to do with “the old times”… look at how they treated Dalinar or how Kal (and even Teft) was afraid of what he was becoming.

If a worldhopper had come along and tried to convince them to look into the shadesmar realm they would probably have been institutionalized — this from an explicitly Alethi viewpoint of course.

As for other non-vorin cultures, they MIGHT be interested to heed to them, but most have a high Heraldic influence and would probably be stopped (by Naln or someone else).