Dutchie is resentful, there's only one Da Bern and he's not.
I actually feel a little sorry for Sanders. He's been been advocating for the same things for so many years, and never got anywhere with them. That must feel horrible. He's just never realized that the reason it didn't happen is because his ideas, when fully unpacked, are just not popular enough to move forward. Imagine dedicating your life to a lost cause and not ever understanding why it was doomed to begin with.
He was outmanoeuvred by the cynical Democrat primary machine twice, yet fell in line as they asked him to, only not to be offered a cabinet post or even a floor vote on medicare for all. Sad, not enviable, and certainly nothing to resent.
He's the personification of the grouchy old hecklers of the Muppet show. People like him because, despite his bark, he's powerless and harmless. Like their grandpa.