Saying Kol was oblivious to Elena's jealousy was an understatement.
He knew all the college girls fawned over him. Knew that it made Elena adorably angry. Like a kitten that believed it was a lion.
Kol also wasn't oblivious to the female humans attempts to flirt. He was hit on at least three times a day. He basked in the attention.
He never told them off either. Not encouraging nor discouraging.
There was a reason. It wasn't just because he liked to be the focus interest of all the girls on the campus. It was tiring really.
He was just waiting for Elena to snap and do something.
It's been a week and she still hadn't yet.
(She does later that day when one tries to kiss him)