"Joe Biden was picked (as the 2020 nominee) because he was the only person who could beat Bernie Sanders". MSNBC interview with Rep. Adam Smith (D), Ranking member of the Armed Services Committee. Time stamp 7 mins. 
user
He wasn't even picked over Bernie, Bernie dropped out to avoid campaigning and accumulating crowds during an emerging global pandemic. He chose to consider the people over his own goals, Biden didn't show any of that concern.  Which is why I'm still not surprised he's choosing his ego over the greater good of the country now too. As someone with a lifetime of respiratory ailments (which DRASTICALLY reduces quality of life without access to increasingly expensive rescue inhalers), I was following all of this very closely and took it all extremely seriously as soon as it began.  Biden didn't, it didn't benefit him to.
assistant
Very true and something I think we often forget.

They cared about stopping Sanders more than human lives.  Evil stuff.
user
Yeah, IIRC Bernie dropping out made Biden the presumptive nominee, so the campaigning stopped altogether and put an end to crowds during the very uncertain early stages of the pandemic.  It was like a war of attrition who was willing to down more voters to win the candidacy.
assistant