Korea is a country shaped their cultures from Confucianism. Confucianism fosters morally good person to be ultimate purpose of learning how to live. In this conduct, people should respect others, 인의예지신(仁義禮智信).
If one is naturally acquainted with 인의예지신(仁義禮智信), it is 대인배(大人輩) which means large mind man. Otherwise, if one is selfish and stupid, it is 소인배(小人輩).
At the Internet, people use this as colloquial purpose, to attribute some people, which removes too strong sense of insulting of criticism, because the two words came from philosophy, not insulting sense.
It is philosophical origin but not used in same way to academic purpose. In academic purpose, it is used to describe moral life such as 군자(君子), which is ethical term.
The guests appearing in television variety program often use this term, as an entertainment purpose.