People are voting for Biden for the sole purpose that Trump deserves not a second term. People literally believe that voting for 3rd party = voting for trump because it is pulling away the biden votes but when asked who the best possible candidate is, their answer is someone that is non-trump and non-biden.
Yes, Biden is not the best president possible(although he is a bit better than the one we have here), but people believe that voting for 3rd party is a waste. If all of them believe that, then we won't get the best president possible. If we all promise to make a change voting for 3rd party, then that they might be a president, maximised goodness. We should not be voting based on who we hate, but who we really want.