The question was, why did Harris lose, and the answer is that many Americans are still too decent to vote for someone who promises to arm the world's most live-streamed genocide.
Millions of potential Dem voters saw atrocities being committed with weapons sent by Biden and Harris. Every day, for over a year. Harris promised to keep doing that. That's viscerally disgusting, and a red line for decent people everywhere.
That's why she lost, which answers the question. Polls before during and after the election back that up unequivocally.
Now, you can argue that it's practical and more moral to vote for the lesser genocide all day, and you can point to all the ways that Trump is worse all night, but you can never, ever convince me that Democrats actually wanted to win more than they wanted to fuel genocide. Because they knew. They knew Harris' numbers, they knew the margins, and they knew what the polls were saying about Gaza. And then they campaigned with Dick Cheney. They managed to lose to a rapist insurrectionist, despite outspending him and his billionaires.
One more time - it's not the voters fault that they couldn't stomach voting for someone actively enabling the mass murder of tens of thousands of children, even if the alternative was openly worse. And it's weird that this is in any way confusing to people.