What one characteristic did all six societies share

Assuming that this is referring to the same list of societies  that was posted before with this question,  the correct response would be "large cities", since all of the societies listed practiced different religions and therefore had different moral codes.

John Brown's Raid was organized by abolitionists who supported freeing the African-American slaves. This frightened the southerners because they believed that such a rebellion was not possible as slaves wouldn't dare to fight against their owners, let alone with guns or similar weaponry. This is why they feared since they believed this might inspire other slaves to try the same.