It seems like agents prefer manuscripts about the marginalized groups BY the writers belonging to those particular groups. For example, white writers aren't ostensibly the preferred choice to write about the experiences of Muslims. Only Muslims should write about other Muslims.
But does this also mean that a writer from a marginalized group shouldn't write about the experiences of a different marginalized group? Like a Muslim writer cannot write about the experiences of a black Christian?
What's the scope and scale of owvoices books?
P.S. This agent talked about the "right credentials" (at 18:55 mark, if the time stamp doesn't work): https://youtu.be/7bnSq-ndy54?t=1133