Post New Left speech focuses on 'safe spaces' which are literally impossible in the public sphere and in locations like colleges and universities where free speech and the exchange of even stupid ideas must exist. One can not learn in a bubble.
New Left speech used the word 'liberation' instead. You can liberate PoC from racist actions in the public sphere and at colleges and university because liberation is not antithetical to free speech and the healthy exchange of ideas.
Liberation is the ultimate victory in struggles against oppression. It takes planning, creativity, and work to accomplish this. It means working with systems to change systems. It treats others as already having an idea of what needs changing but invites them to raise their consciousness so that greater empathy influences faster change. New Left speech was the basis for the generation that truly brought about LGBT marriage rights.
Creating safe spaces, on the other hand, is temporary. It is the small fix instead of systemic change. It seeks to protect marginalized people from the effects of 'privilege' without actually making the necessary systemic changes. Safe spaces can then only be maintained by calling people out constantly on their 'privilege' and attempting to check said 'privilege'. It becomes antagonistic suggesting constantly that the other is not an ally but an enemy of change. It ultimately fails to determine what are the final end goals. To maintain the safe spaces and act in such a manner with regards to 'privilege', it stifles free speech and the exchange of sometimes conflicting and very uncomfortable ideas.
As long as young activists today continue to be semantically influenced by Post-New Left speech and fail to learn from the activism of generations before them, the change they seek will not only not occur but in the process greater degrees of conflict will occur and free speech, in this case, on college campuses becomes a target of their ineffectual rage.