I'd chalk that one up to internal ROK politics. It's the opposition leader banging the drum to say that the current admin isn't doing its job related to security.
I'll put it this way, losing SK would be worse than taking ten nukes to our cities. We're in full-bore if something goes down… but, frankly, the ROK is trained and capable of holding their own should the DPRK get aggressive. Their best tactic is to hand their soldiers spears and tell them that there's food in South Korea, if they can get to it. As opposed to a military crisis, it would turn into a humanitarian one.