There are a lot of attempts to push polyamory on white-collar and chattering-class culture, but many men in the USA seem to push it so they can tell their primary partner "I sleep with my groupies because I am polyamorous" and tell their groupies "who cares that you have a boyfriend, how about polyamory?" It also lets insecure men show off that they have not just one hot babe but several, and we know many rationalists are desperate for the rest of the world to recognize their genius. The problem, to be clear, is not necessarily with polyamory, just with people who use it as a way to get a gang of domestic servants.
I still have scars from events like the ones documented at https://allegedlythewebsite.org/ So many men in the skeptic and adjacent blogosphere used "sex-positivity" to mean "I can hit on you and encourage you to bottom at kink events, and you can''t say I am creeping you out or you are looking fro a job not a playmate." Similar dynamics are common in academia, polyamory was just one trendy excuse in the 2000s and 2010s. Scott Alexander experimented with polyamory and was living with a sex blogger in 2013 and I think Yud had connections in the NYC poly and kink scene.