They did all of that during the primary against Bernie Sanders. They went so far as to call him a Russian plant. And the rigging of the Iowa caucus result reporting was unconscionable. They only reported districts that Sanders was not leading in, making it look like he lost. It took a week to report results districts he was popular in and he ended up winning the popular vote.
He lost the 2019 primaries even worse. Minorities see class reductionist for what is is, racism from privileged middle class whites. It's clear that Bernie doesn't give a fuck about black people and they killed him for it.
https://m.youtube.com/watch?v=nDO2kHGEoY0