I find it unsurprising that the most vocal proponents of the marketplace of ideas tend to be white men with extensive media reach who are unfazed and unaffected by other white men with extensive media reach who use said reach to punch down on marginalized groups. It’s an abstraction for a great many people who, approximately one year ago, were not getting beaten by a gang of pole-wielding white supremacists in a parking garage in Charlottesville. But for DeAndre Harris and countless other people who have been on the receiving end of neo-Nazi violence, it is a lived reality.
One means of bridging this gap between the sterile abstractions of privileged white men and the violence inflicted on the targets of white supremacists is empathy, and that empathy is communicated by choices and actions, not by wielding idealism as apologia for hate mongering. As you have astutely observed, the marketplace of ideas does not yield rational outcomes. Nazism is an ideology based on fear and hatred, rooted in irrational and pseudo-scientific beliefs, yet it is still marketable precisely because humans are not rational actors. And it was an unhinged neo-Nazi who killed Heather Heyer a year ago for no reason other than adherence to this very ideology. Choosing viewpoint neutrality (“both sides”) over viewpoint objectivity (“Nazis fuck off”) in the face of this violent reality has consequences. Empathy is understanding that and acting accordingly even when you don’t bear the brunt of those consequences.