In any other context it would probably hit the Wrong button for me, but framed this way I think it's actually kind of sweet. Most teenagers would be allowed to keep their romantic delusions intact for a while longer, but this Lana has already had that idealism shattered. Even knowing that she minutes away from a mindwipe that will render it all null, it's a little sad. Superman sympathizes, and I think they both know that's all it is. It doesn't strike me as a lecherous move in his part, which is what brings it within the range of okay for me, I guess?