We do it by empowering the communities itself, and teaching them to liberate themselves. Its not perfect, but afterall no solution is. You still get cases like the atrocities  individuals of the Black Army committed against the Mennonites, and the ones committed by the CNT-FAI against nuns and priests. They are horrible actions, and while I still support and admire the groups I still condemn those actions and wish to learn from and prevent them in the future. And not that I am excusing it with whataboutism (just trying to avoid anybsort of singling out of anarchists about this), but this is not a unique problem with anarchists. Every group is guilty of doing similar stuff, and I feel anarchists are better about reducing, resisting, and condeming those actions than other groups. I think part of it is simply the culture and beliefs of anarchists that helps prevent these kinds of acts, but also like I said the community empowerment that comes with anarchism. I think it is also important to build a culture of accountability within anarchist groups, and to develop structures that reinforce that. What all of that looks like is stuff we are still figuring out and learnjng from, but we have progress made in that regard. “What about the rapists” is a good book discussing ideas on community safety and justice without cops, which some could be extrapolated to revolutionary militias