Categories are a human-defined thing, not something that is "out there". The point is to try to understand human behavior better, and that includes questioning

Categories are a human-defined thing, not something that is "out there". The point is to try to understand human behavior better, and that includes questioning pre-existing categories, and perhaps, defining new ones? Quoting the abstract again: "Latent class analysis revealed six distinctive "types" of heterosexually identified students whose last hookup was with a same-sex partner.[...]"