As liberals see it, they are 100% responsible for every advance or progress made by either women or blacks. Therefore these two groups “owe” liberals, and if a woman or black person dares to be a conservative, they are savaged as somehow ungrateful and treasonous. As they see it, every woman in this article owes their career to Gloria Steinem, and therefore they have a moral obligation to agree with her on any point Steinem wishes.
I think the commenter might be on to something.
Leftists do savage any woman or minority who breaks political ranks. I have always assumed they did so because leftists always argue that any honest person immediately sees that their ideas are true. An entire group only holds the same idea if they believe the idea obviously valid. For example, everyone in the western world believes in Newtonian gravity and a heliocentric solar system. Creating the perception of uniformity of thought on the part of a protected class allows leftists to argue that those who disagree with them do so purely out of a bigoted refusal to adopt the perceptions of the protected class.
However, it could well be that many white leftists believe themselves as a group responsible for all good things that happen to members of a protected class, and that therefore all members of a protected class owe white leftists their political loyalty and allegiance. When leftists see an individual member of a protected class rejecting leftist ideas, they feel betrayed on an emotional level and view the individual as a traitor and an outcast no longer deserving of civility or any other consideration.