The problem is Biden probably needs outreach to Bernie voters, loudly questioning whether Bernie voters are going to sabotage Biden is probably harmful to these efforts. But all of the donut crap heads, Hillary staffers, DNC people, mainstream pundits all love the Bernie is going to eff up Joe, so it just becomes a self-fulfilling prophecy. You have Hillary herself arguing Bernie didn’t lift a finger to help her in the general which is just probably false, but the narrative is very helpful if the goal is finding excuses for why Trump best Hillary and has a decent chance to beat Joe. It is a very bad narrative for Bernie voter outreach.