Aight, I'll elaborate.
In terms of actual record, Hillary's "baggage" is basically being implicated in DLC style politics from the 80's and 90's: hawkish on foreign policy, punitive on drugs and crime, soft on banks, giving away jobs through free trade, etc. These are the areas on which she's been attacked the most throughout the campaign, and they're subjects where Biden either shares or outdoes those vulnerabilities. If it's baggage for her, it's baggage for him (and if it's not, then Molotov is right).
Now some of them are more of a problem in a Dem primary than in the general, but if we assume a centrist record is a plus with the electorate, then we can't also say Sanders would be a better matchup against Trump.