Unfortunately, the radical left's contempt for the bourgeois nuclear family is only exceeded by their far greater contempt for the traditionalism of extended family structures, which often entails "staying put" for multiple generations in comparatively rural towns and villages - far different from the inner-city concerns of the rest of the BLM movement, and the leftist progressive movement more generally. So, while there's much to say for what you're advocating here, it's not the kind of change that BLM is going to meaningfully pursue.