It's not about being unwillingly celibate there are laws about taking advantage of people who are classified as mentally retarded. People who's IQ’s are so low they really don't understand or can't understand what sex is can be taken advantage of by sexual predators.
As another FReeper said, they may understand that sexual stimulation feels good but that's about it. Many of them won't understand that is how this process creates a child. Plus a lot of them if they are raped/molested can't report it because they are non verbal. Let me put it to you this way, a lot of them have the mentality of a 2, 5, 8 or 10 year old child, or some where in between. This makes them the perfect victim for these sickos.
Oh yes it is. Essentially it says that she is not capable of giving consent, and that any sex with her is rape.
Just exactly what is the difference between the law deciding that she can not give consent for sex and the law forcing celibacy upon her, without her consent?