It's literally not. That's functioning on the assumption that -
Hillary is as deeply stupid as Trump
Hillary is as narcissistic as Trump
Hillary would surround herself with sycophants like Trump
Hillary would actively reject expert advice
I mean we could go on here. It's not conjecture, we can look at what Trump has done and who he is, and we can look at what Hillary has done and who she is. Do we know exactly what she would have done? No, that's silly, and nobody would claim that here. But would she have likely reacted sooner, like when intelligence briefings started appearing in front of her (she reads those!), taken the early advise of experts like Dr. Fauci seriously (she likes experts, a lot!), and generally hogged a lot less airtime to promote her campaign and attack the press? Yes.
And so would Biden given his history and who he is.