Diversity of viewpoints is not good when the views pertain to things like a marginalized group’s right to exist. I don’t need to hear a “diversity of viewpoints” on the issue of whether you deserve to be alive and have freedom, for example — I know in my heart that you do, and any argument to the contrary would be morally abhorrent. I’m generally pro marketplace of ideas, but when hate and misinformation make up the bulk of a group’s positions, there is no common ground, and no value in trying to find it.