Like, I don't even know how to explain this any simpler:
Biden lied to everyone about being the new FDR, ending the forever wars, stopping police violence, dismantling the migrant carceral system, going after the fascists - and a lot of us suspected he was lying, but voted for him anyway on the off chance it happened. Just for the CHANCE things might change.
Harris didn't even respect her base enough to lie; she ran a campaign for donors, NatSec ghouls and cracker suburbanite Republicans.