Well, humans have something of an innate need to gender our relationships just because only one pairing actually propagates the species. We're moving beyond that, by degrees, as a civilization. But there's still the crushing weight of formality that's been ingrained in us to view things a certain way and label that as "normal".
The contrast here is that troll society also has a biological imperative enforced on them by the breeding drones, but they still have the same types of ingrained imperatives in seeking that "one true relationship" in each type and classifying that relationship as some kind of ideal. It's just as much overthought melodrama and posturing that stresses people out and causes unhealthy tension.
The unhealthier bits are pretty much the core of Vriska's, Equius', and Eridan's character profiles. Eridan couldn't cope with social pressure, so he built the hypocritical self-superior facade as a defense mechanism until it failed and he emotionally snapped. Equius is so ingrained in the system that he emotionally suppressed or even fetishized his true feelings (apart from his weird blather he genuinely cared for Aradia and Tavros, helping them with robot parts). Vriska spent most of her life in two emotionally abusive relationships - spidermom and the Marquise's journal. Trying to fulfil those obligations, real from spidermom and culturally imposed by the journal, caused her to make horrible life choices and generally be the huge bitch that had to be stabbed to death. Looking at her choices objectively was the only way she was able to move on and accomplish things without much direct force, even if the self-aggrandizement is still there. It's why pirate!Vriska calmed down from watching Aranea's idiocy, and the current alpha is still alive thanks to an Egbert facepunch.