Are you of the mindset that you can only have either punishment or rehabilitation?
im of the mindset that punishment of any severity is guaranteed to lead to negative reinforcement. the majority of serial rapists are psychopaths and if you punish a psychopath they will just find more elaborate and subtle ways to get what they want. sending one through prison could easily spit out a 'rehabilitated model prisoner' on parole who continues raping but is better at hiding it.
actual rehabilitation and humanization of psychopaths is more mutually beneficial than punishment of any sort. whether they have any empathy left or not is besides the point; their serotonin reception can easily be balanced out through medication/therapy and they can learn to understand how preying on other people is going to lead to a less than ideal outcome for themselves.
Also, elaborate please.
I can imagine a person who absolutely disapproves rape and therefore disapproves rapists.
see it like this: what happens when you send a rapist to prison? chances are they themselves will be raped or they will rape someone else in that prison. some people actually have no qualms with that and just pass it off as 'they all deserve it.' ie not anti-rape but purely anti-rapist. it all comes down to who deserves what, which is based on arbitrary, subjective morals. considering a significant portion of rapists/child enthusiasts were once raped themselves, the morals tend to get muddy
anti-rape mindset says that nobody deserves to rape and nobody deserves to be raped. so naturally the best course of action is to prevent rape before it happens rather than just further isolate and antagonize people who aren't predators yet but tend to rationalize it. ideally, everyone wins; you get people who justify predation to understand that it's mutually damaging and unsustainable, and encourage them to talk to someone about it before they completely rationalize violating another human's basic rights.