No disagreement about complicity. A victim of a crime is never "complicit" in the crime, even if they might have done something which made it more likely that the crime would take place. That is true whether it is a rape, a mugging, a burglary or a car theft. The fact that courts sometimes seem to think in those terms is monstrously unfair, especially in the case of rape.

There is an enormous difference between making a stupid mistake and committing a vicious crime, and sometimes the language of blame and fault can blur that difference. If a girl gets drunk, and a man takes advantage of this to rape her, it is completely wrong to imply that by getting drunk she was asking for it, and that the guilt of the man is in any way reduced. No one would be likely to suggest this kind of implication in a case of male on male rape.

But imagine a slightly different scenario, in which a friend had spiked the victim's drink as a joke and then drifted off - would we say that the friend had no kind of responsibility for the unintended events that followed when a third party moved in? Not the kind of responsibility that in any way reduces the guilt of the rapist, but the kind to cause bitter regret.
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As for the notion that a perpetrator's guilt is somehow reduced if there is seen to be some blame attached to another person, that would seem to imply that participants in a gang rape were less guilty than an individual rapist, which is surely absurd.