Hansol didn't know anything about being an omega 

He grew up in a traditional pack where being an omega was seen as being a disgrace 

He was never told how she should act or how his body would change over time

He knew nothing of pack dynamics or pack traditions.

Idol AU Where Alpha, Beta, Omega statuses stand

Members can be in the same pack as group but don't have to

Namjoon is in Got7's pack instead of BTS's

Omegas are courted before they chose what pack they want to join

Seventeen never told Vernon any of this and were just going to make him believe that he had no choice but join their pack

BTS pack finds out about this and gets pissed

Vernon is confused