It's just an illustration of two females that so happens to be shown in a romantic light. The only one bringing up anything about "heterosexuality being rare" is you. No one is "belittling" heterosexuality, (I find this whole conversation to be hilariously ironic.) sexuality preference isn't some kind of twisted competition where the "bigger one" is the best, and the "rarer one sucks", it's a preference, just that. Chill.