I agree that that was the wrong move then and was probably a desperation attempt out of frustration at the end of an unfair fight and hopefully something he regrets. It's not apples to apples though. Bernie was always against super delegates on principle and what was most undemocratic last time were huge swaths of super delegates declaring for Hillary before others even entered the race. Also having Hillary leave States where Bernie won in landslides with more super delegates. As has been well documented the whole DNC was owned by Hillary from the beginning.

Bernie's team tried to fight for the total elimination of super delegates for 2020 but Hillary's team stopped him and they were only able to get them moved to the second ballot. Things appear more democratic this time thanks to the efforts of Bernie's team. If Pete and Warren are so against the electoral college then it is hypocritical of them to not give the nomination to the person with the plurality of pledged delegates. If it's the will of the people it should be the will of the people.