The empathic fallacy is defined as “the belief that one can change a narrative by offering an alternative narrative, in hopes that the listener's empathy will quickly and reliably take over.”
The marketplace model infers that notions of common humanity, decency, and rationality will prevail against ideological forces like racism, sexism, classism, and other prejudices. One need look only to contemporary movements around Black Lives Matter or the gender pay gap, to see that prejudice thrives despite rational arguments against it. In this case, there is nothing to say that encouraging all ideas equally will not lead to deepening prejudice and hateful ideologies. A belief in a basic threshold of human empathy is naive. And bears little relation to the lived experience of many people world-wide.
The marketplace of ideas is about showcasing ideas and giving them a platform. That is important to protect free speech, but only those that stand up to scrutiny will survive. Those that do not, will not. Empathy is less important than the soundness of an argument in many cases. And the Western social consensus on what this means, is largely based on liberal principles that promote equality and reason, over hate and hierarchy.