100 humans, including a winner of a beauty pageant, are brought up to aliens who want to learn more about humanity, and ultimately why humans didn’t save planet Earth when they knew century earlier it was being destroyed and beyond the point of no return.
That sounds like the short story "The Janitor On Mars" by Martin Amis, published in The New Yorker on October 26, 1998. Link to the abstract is here.
From an essay about the story:
The Janitor on Mars is about the sole surviving Martian. Mankind has crossed some threshold called "the tripwire," and as a result the Janitor took over CNN to broadcast his presence, and invite a coterie of the intelligent and the beautiful (excluding only politicians and clergy) to come to Mars and learn the Janitor's secrets. So a mission was cobbled together, with some help from the Janitor, and eighty-five or so people went to Mars to hear him out. When they arrived on Mars, inside Olympus Mons to be precise, the first thing that they learned was that the Janitor was a robot, and that all the Martians were gone. The robot told the tale of the history of the Martians, who matured as a race very quickly after the planets of Mars and Earth were formed, built up a glorious culture, then, mostly out of boredom, blasted themselves almost out of existence. The Martians, in keeping with legends that would be written about their patron billions of years in the future and an entire planet away, were a very warlike race. They were also highly advanced. In an uncountable series of wars they destroyed themselves in seconds, then built their culture back up over hundreds of thousands of years only to do it again and again and again.
The New Yorker link has a link to the story in its archives, but you need to be a subscriber to read it.