> I'd at least like to know what is the end game here. Have those groups effectively given up any hope of changing the country and mainstream society at large, so the new strategy is now retreating into gated communities

I noticed this occasional tendency in the west to analyze an action or behavior by hypothetically scaling it to way beyond the scope of the actual action or behavior, and I've been wondering if this is some kind of judicial application of Kantian thinking?

I'd push back on that and say, not everything has to be scaled. Not every behavior is an indictment of other behavior. People doing things isn't necessarily an argument that all people should do those same things. Nor is it an indication that those people only want to do those things that way - just because some black people want a reprieve from whatever their perception of day to day western life is, doesn't mean they've "given up" on making any changes to that society.