You have to remember that it was common in her district for people to literally just die from starvation in the street. She herself was bordering on starvation before Peeta tossed her that bread. When you're starving (or fighting for survival and your family's survival... dependent on a good hunt or forage) there's not a lot of time or energy people can (never mind want) to put into thinking about life outside survival. It's one of the reasons the Capitol is so effective in all their propaganda.

And her relationship dynamics are simplified... because she's a sheltered 16 year old. It's incredibly realistic for the character, her age, and setting imo.