I'm only responding to the assertion that asking "what cis women think about playing trans women" is morally equivalent to asking racists whether they want to play against black people.

But I think this part is where the disconnect is happening. Before this decision, cis women and trans women were both components of women's chess. The act of conferring with only a subset of that group implies that the other does not fall into that category. Relying only on the majority group's opinion on the status of the minority group is itself an assumption that one of the groups inherently belongs less than the other.