The answer is that mostly they have the dysfunctional mind, with the emotional baggage of fear, anxiety or other mental conflicts and past hurts in interpersonal situations.
They fear experiencing invalidation from the target of attraction because they use superficial categories to define the self and others as well as to predict the effectiveness of their possible relationships, ignoring the affection messages from the real people who are attracted them.
The basic ingredients for love As demonstrated by studies on interpersonal attraction, creating and maintaining love involves validating communications between the partners on a variety of issues, including understanding and concern for the partner's personal and emotional needs, developing companionship, physical attractiveness, cultivating and nurturing physical, emotional, intellectual and spiritual well beings, respecting, supporting, forgiving, accepting and encouraging, expressions of appreciation and affection: sexual pleasure and fidelity, commitment, shared activities, as well as the absence of controlling, defensiveness, contempt, stonewalling, and blaming, among other factors.
To accomplish the above tasks, the partners need to engage in the meaningful interactions (face-to-face interactions, including both verbal and nonverbal communications), which allow one person to give to and receive from the other.
All categories are just the maps or substitutes of social reality, not the reality itself.