For the generation of Progressives/liberals who came to maturity during and after the ideological conflicts of the 1960s, there is nothing controversial in the Harper's letter stating that... “the way to defeat bad ideas is by exposure, argument and persuasion, not by trying to silence them”.
But... this is now precisely the point at issue. This new generation of LW so-called Progessives believes that progress is achieved by silencing unwelcome voices rather than by defeating them in debate and as true Progressives they have no tolerance for dissent and no wish to debate. Their behaviour is way beyond just being acrimonious.

Take the BLM founders for example... they claim they are trained Marxists. They study the works of Karl Marx, the "father" of communism who wrote "The Communist Manifesto", the bible of communism. BLM claim to be social justice warriors, they hide behind the mask of racial injustice and attack anyone as a racist who disagrees with them.

The Progressive Left are into every victimhood issue you can point a stick at. Virtue signalling, identity politics, anti-capitalist, racial, sexual, etc, etc, etc... Supported by Left leaning Parties the world over... Greens, ALP, Democrats (US), Labour (UK)..........

How dangerously stupid is this getting....?
The brilliant Killing Eve actress Jodie Comer is currently receiving all sorts of stick for dating an American man who votes Republican.
A woman was killed the other day for saying "All lives matter"...
Universities and their newly indoctrinated Leftist students have created, new infringements... called micro-aggressions — word choices or actions that connote or encode hidden violence.
Students have begun to demand “trigger warnings” before being exposed to texts or ideas that might recall a previous trauma. Spurious claims came flooding in that text triggered an undesirable emotional response... and that in itself, was enough to castigate the author and threaten the Publisher. so now emotion rather than reason replaces all literary standards for evaluating text.

Bad ideas, couched as good intentions... are setting up a generation for failure.