Democratic Primaries

That is because all populist movements draw a lot of social conservatives who are motivated by antagonism toward others. So much so that their influence is always defining. LW class warfare and RW nativist, nationalist, or white power movements differ in how relatively mild or rabid their dominating influence is, not whether it exists.

Sanders, the far left class-warfare revolutionary, had to choose:

* Draw only LW idealists to a little statement campaign that settled for claiming Democratic ideals for their own (including equality) and thus anything we do could be called their victory, or

* Try to create a genuine movement by drawing large numbers of aggressively antagonistic (toward everyone) mostly white populist types, who would otherwise go to Trump, and to use them to try to burn down the national barn for him.

And Sanders ambitiously chose the latter. One guess why.