Curious -- why specifically do you think a romantic conflict will (or should, if you think it should) get the booting more than a standard quest-type one?

The stated or implied sexual overtones leave the door WIDE open for approval/disapproval. Twilight deals with adolescent lurve, and way the two main characters deal with their attraction; any decision the author makes on their behalf is subject to approval or condemnation by adults, parents, and teens.