Dr. Dwayne
Self proclaimed tagline king.
I think he chose not to attack his old friend Joe Biden last year and prioritized that relationship over the needs of his donors and the people who desperately need healthcare.
So he cared about the party and the balance of power in the three branches of the US government. This criticism is fair but should recognize his motive being the need to get Trump out, something which I think Bernie might have struggled with had he won the nomination and Trump bestowed some tag like 'Bolshevik Bernie' on him.