An overall disdain for anything too trendy or popular.
My teenage family members live and die by the trend cycle. Teenagers have always cared about what's cool, but now the trend cycle is so fast it's impossible to keep up without spending inordinate amounts of money and generating tons of waste. It also just doesn't seem great for their self-esteem.
I was a teen in the mid-2000s/early 2010s hipster Tumblr era, which of course came with its own issues. But at least the trend cycle took a few years, and if anything I liked was unpopular I could just roll my eyes and say it's just too obscure for you normies to understand.
I wouldn't be concerned about trending itself, it's that people seem to be favoring trends that are objectively bad. The pandemic people kept saying it wasn't real and would go away when summer of 2020 came... but that proved wrong, and so few seem to want to learn from the lesson of going against science in favor of Fox News or whatever other negative trend that crowds keep following. If we were trending towards building affordable houses for more people and sheltering the homeless and not making rent lock people into jobs they don't want - I'd thing it was progress. But right now, the crowds seem to be flocking to some negative-oriented Nazi kind of shit.
I respectfully disagree. Yes crazies are getting crazier and louder, but overall more young people are trending left -- and further left -- than ever. I don't think bigotry is particularly cool or trendy to most teenagers.
It isn't just their words, since 2014 they believe all kinds of wild things, and the pandemic was just one example of how they act out on these belief as business owners, neighbors, organizations. It isn't just politics.