Biden is actually right about that. Let the process play out, ballot after ballot if necessary. The problem is with the superdelegates. They are not elected delegates. Yet they get to vote at the convention. That is about as undemocratic as it gets.
On August 25, 2018, the Democratic National Committee agreed to reduce the influence of superdelegates by generally preventing them from voting on the first ballot at the Democratic National Convention, allowing their votes only in a contested nomination.[1]
https://en.wikipedia.org/wiki/Superdelegate
There is no obligation for a nominating process to be “democratic”.
And you thought the DNC was set up to implement a democratic process? Really? It is a corrupt organization that because of the dominance of essentially a two-party system, yields tremendous power. It is an organization set up to, among other things, nominate a presidential candidate every four years. It's no different than the Green Party, the Constitution Party, or the Party for Socialism and Liberation, except the DNC has tentacles so deep into the government, it makes, changes and plays by its own rules.