You're absolutely right, it is completely unreasonable to put up defenses against most cases of rape. But does that mean it's pointless to try and safeguard against the others?
It's pretty much impossible to do, unless you want to distrust just about any man.
Yeah, because all men are evil rapists just biding their time. Nailed it.
Sorry, but if you want to dramatically lower your chances of getting raped, don't dress like a slut, don't get drunk around complete and utter strangers, and don't go wandering off into quiet little areas with people you don't trust especially in a situation that is otherwise rapey. Guess what! Do those things and chances are you'll be a genuine outlier if and when you do get raped, and in those cases, you will not only get, but deserve, any and all sympathy others have to offer.
It's all about not being a completely and utter moron. That's not "slut shaming" or "victim blaming," it's "quite being a fucktard"ing. Want to drastically lower the chances of having your car stolen? Well don't leave it idling with the door wide open when you run into a store, especially in a neighborhood known for its criminal element. That kind of logic is exactly the same sentiment behind the "don't dress like a slut, dumbass" statements.
Does it mean having your car stolen or being raped isn't still a horrible thing to have happen to you? Nope. Does it mean the criminal doesn't deserve to be prosecuted under the full weight of the law? Nope. However, and most importantly: Does it mean you deserve any sympathy for all but inviting someone to victimize you? Nope. Just like the guy who left his car idling.
Sure, you can do whatever you want. It's your body/your car. But don't expect anyone to feel bad for you when you do something stupid with it, not because you deserve it, but because you shouldn't have been such a fucking moron in the first place.