>>116054116If I'm being insulting I'd say that cuck/NTR plays into insecurities varying from being unsure of social, economic status, and masculinity (if you want to look at it from a left lens), and a crisis of relationships, fidelity particularly by women, and family (more of a right lens). If you're insecure seeing something that brings up these insecurities doesn't feel good. If you're unable to emotionally self regulate, you need to vent about it, to displace those negative emotions onto an external target.
Of course, "respond to what people are saying by psychoanalyzing them" is usually a provocation at best and a way of dismissing people outright at worst. So it's also possible that people just don't like the genre and are sick of it showing up everywhere. Particularly since there's a strong crossover between NTR that and other kinks.
There's also the possibility that people are just invested in the fight now. You can see the number of people saying things that are just flat wrong or only supportable by an extremely tendentious reading, which is usually a pretty good sign that an argument has become an end unto itself rather than a way of convincing other people.