Where I live, recently, we were facing different cases of (young) men and womyn alleging about rape in the anarchist background and other close "militant circles" (of people who know at each other in these circles). In much cases, it happened to be true, and in most of the cases : rapers were protected, and victims or survivors (use the word you prefer) were systematically accused to be liars...
And sometimes, there is no logical explation to people who lie about serious shit and we have to face it. But that doesn't mean that we can't react and act in consequences when we hear this kind of stories. That doesn't mean that anti-patriarchy isn't an important issue, or that (anarcha-)feminist tools and practices are to blame, but just that we have to use violence or exclusion carefully when it's needed and with possible self-criticism, and try not to act for someone else but with and in solidarity. And that's the kind of best arguments that anarchist feminists or other feminist friends gave me about this kind of situation.
As dot wrote it some months ago, I think that in any case we should always take this kind of accusation seriously even we don't have any "proof". Which doesn't mean that the individual who is accused have to pay for something (s)he haven't done, but that maybe it's better to put someone in trouble for a little while and apologize if you realize that it wasn't true than to do nothing just because "sometimes, women lie about rape" (which is a very common misogynistic cliché).
More than this, I recently read this terrible text called "Safety is an illusion" by anarcha-feminist Augustia Celeste in her book "the Broken Teapot".
It's a must read on this topic. On the one hand she have a radical and large definition or rape that she don't define in terms of the judicial system, and make a difference with abuse, and advocate the possibility of being violent to reject a rapist even after it happened, and on the other hand, she have a very critical point of view on some usual methods, practice and claims we often met in radical, feminist and anarchist circles about rape. Especially arguing that there is no real "safe space" (and that such claim is reactionnary - the obsession for "safety"). I trully think that this shouldn't discourage ourself to create spaces where it's more and more difficult for men or even people in general have dominant or oppressive behavior, but that as Augusta explain it : it's not all about "behavior" (jesuit/behaviorist mentality) or education. It mostly about systematic oppressions and balances of power and forces so strong that they couldn't really be challenged by anything but an abrupt and radical revolutionary type of social change.
I trully think it's part of the answer because we couldn't really answer this question in facing it only on a micro-social point of view. We would never have enough "guides" and "critical manuals", and the "critic of the critic" to solve such questions. We have to destroy rape culture and sexism as social "relationships" (some feminists even define it as "non-relationship"), and to do so both trying to think and act here and now about these questions in our "communities" or backgrounds, but also to attack and shut down the whole statist, heteropatriarcal and capitalist society.