I'm not sure it is necessary to "understand" others' experiences to act for their benefit. If we can understand that people are suffering intolerably because of conditions we may be able to ameliorate, why does it matter that we have not actually experienced that intolerable suffering? We need only observe it and want to fix it.

Where the train goes off the rails is in the belief that victims are uniquely able to prescribe remedies. That's simply not true. A doctor who has never has a broken bone is better able to set one than the layperson who has one. There's just no logical link between diagnosis and treatment.

Victims of oppression may well have some uniquely valuable insights, and the best solutions may in fact come from people who are in fact victims, but that's because the victim population contains the largest proportion of people motivated to find solutions, not because victimhood confers unique competence in the matter.

So, I come down with on the side of epistemic isolation in the "Nobody Knows the Trouble I Seen" sense, but I just don't think that fact carries much weight in the search for solutions and so is no reason at all to discourage outsiders from trying to help.