I see it as more of a deliberate community building choice, one that we've seen for decades and one that's more popular now than ever, I'd argue, and not some "millennial" propensity towards tribalism.

Every brand/product/service/etc is trying to create communities around themselves, with fan clubs, VIP memberships, social media groups, email lists, Zoom/in-person conferences/webinars, etc.

It used to be you had to have a ton of reach and value to pull those off before the internet, now every project has marketing and social media people doing the same thing online.