I think this is not new because — generalizing — unions didn’t maintain progressive unity after the civil rights movement. In 1968 and after, too many of union members voted for Nixon and then Reagan.
So . . . as strange as it seems, on the left, there was more support from corporations for cultural issues related to race and gender. I think that’s partly why HRC’s base includes so many corporations in addition to unions which are comparatively weak. Unions are too weak generally.
Even Sanders supporters often owe more to a corporate economic base than to unions. That makes no sense in terms of political power. The left has gotten a lot of political work done by organizing general strikes, secondary strikes and boycotts.
