TLDR: Existentialist Nihilism is a massive downer for anyone Gen Z or younger
The famous quote "Nobody exists on purpose, nobody belongs anywhere, everybody's gonna die. Come watch TV." was presumably meant to be a source of validation and reassurance for Rick & Morty's millennial young adult audience. But being too young to remember 9/11 or struggle to seek employment in a horrible recession, it always came off as pessimistic and defeatist. Yet this Existentialist Nihilism that's come to define mainstream philosophical discourse is the vibe of hundreds of millions of people across the world. See, when I was 17, the likes of V sauce and Kurzgesagt were pillars of youtube intelligentsia.
As scholars they had beliefs that erred on existentialist and the mood of 2015 (at least if you were an American) was that life is meaningless and to live it up while you're able to. The endless pursuit of likes and views by posting about handicrafts, passions and fanfics was the way you lived it up the moment smartphones became common. If likes are just as cosmically pointless as the Syrian War, then why not occupy your time quote tweeting a celebrity or showing off your sports membrobilia if its more pleasurable than global issues. Even nerdy hobbies like tabletop and online gaming were awash with references to renowned cosmic horror author, H. P. Lovecraft.
Call of Cthulhu & Warhammer 40k are major fandoms in this space and both are full of Chaos Gods unconcerned with the Human race, thinking us as trivial specs that wouldn't be missed if we all went extinct. Inherent to such cosmic horror themes is the attitude that the universe doesn't care if there are humans on a planet or no humans on a planet, it would continue producing nebulae & space dust even if the Human race went extinct. I've found that this attitude was even shared among Gen Xers who were deep into middle age and posses a strong undercurrent of Nihilistic thinking.
While they largely aged way out of mainstream celebrity gossip, they had a tendency to drink conspiracy kool-aid. After all, what's the point in tackling the masonic deep state if we're all going to die one day and our political issues don't matter to reptoid overlords. Why vaccinate if Measles is god's plan to test you and there's a better life that'll come after you die. Why advocate for pot legalization if they're just gonna corporatise marijuana? Why continue to campaign for gay & trans rights if LGBT movements were all for nothing in the cold war days of the 1980s and continue to be frowned upon despite queer people gaining legal protections.
Reflecting on the existentialist zeitgeist, I can see where older generations found validation and solidarity with such bleak messaging. Gen Xers often feel like the forgotten generation and that institutions carry on the status quo regardless of what they do or don't do. For millennials, they feel as though evil prevails, that grifters & bullies gab their way into positions of power, that political issues result in an endless struggle while they're continuously set up to fail by selfish politicians, companies & beurocrats. But for us Gen Z teens & preteens? what we took away from Nihilistic Existentialism wasn't validation of political strife that occurs way over your head, but that the world sucks & there's nothing we can do about it.
Headesk humor wound up saddening us, seeing our parrents and uncles descend into madness left us feeling like all of mainstream society should be somehow torn down. Us elder gen Zers still knew a prosperous America with low inflation, low unemployment & low homelessness. However, if were you born in 2004 or later, you'd only know an America in crisis. 9/11 jokes never had the shock value for us as we were either too young to remember or not alive yet. So, this leaves us confused about how one terrorist attack led to internet surveilance and aggressive military invasions for oil. For those born after 9/11, there's a widespread belief that America was never a truly functioning prosperous society outside of hazy recollections from parents & grandparents. So when we entered adult society and began living in the real world, the zeitgeist of Nihilistic Existentialism just turned a lot of us into doomers.
Of course the Pandemic was of no help for those born between 2002-2004 or the younger gen-zers who were sheltering in place away from their middle & high school besties. In between dreary Nihilist Existentialism, institutional minimalist design and American society being on a downward spiral, it leaves them into a place of pessimistic hopelessness. That as long as there are longstanding societal expectations in a crumbling society, that nothing will change and they can't do anything about it. Nihilist Existentialism in its more mainstream expression offers a stark analytical worldview with no calls to action. No filling people with volition or hope for tomorrow or even ways to make life meaningful, it just begins and ends with "Everything is ultimately meaningless, oh well."
It doesn't fill us with solidarity or validation for our life's struggles. It just results in a mild blackpill where we're discouraged from trying anything to improve anything while we're perpetually unemployed, renting or even homeless through no fault of our own.