Let me tell you a story:
Tortoise: Not so. You can only do what your brain will allow you to do, and that is very crucial. Let me ask you another question. Can you decide to kill me right now?
Achilles: Mr. T! What a suggestion! How could you suggest such a thing, even in jest?
Tortoise: Could you nevertheless decide to do it?
Achilles: Sure! Why not? I can certainly imagine myself deciding to do it.
Tortoise: That is beside the point, Achilles. Don't confuse hypothetical or fictitious worlds with reality I'm asking you if you can decide to kill me.
Achilles: I guess that in this world, in the real world, I could not carry out such a decision, even had I "decided"--or claimed I'd decided--to do it. So I guess I couldn't decide to do it, actually.
--"Who Shoves Whom Around Inside the Careenium", by Douglas Hofstadter, in Metamagical Themas
I have to dispute the claim that all people are potential murderers (or all men are (potential) rapists) simply because they have the wherewithal to carry out the act. Picture yourself standing next to your best friend and holding a loaded gun. Could you shoot him (or her)? Wait, let me guess, "if I wanted to," right? But that's just the point; you don't want to, and you never will. There is nothing I or anyone else could do to make you want to do it either, not for love or money. And therefore, you cannot, in any meaningful sense, do it. Sure, Andrea Dworkin can posit a fictive world in which you could, just as I can posit a fictive world in which bullfrogs have wings so they don't bump their asses when they jump. Both worlds are counterfactual.
(see also free will vs. free won't)