It isn’t. If you’ve ever been raped in your sleep, by someone, then you’d understand. My husband knew that his half brother’s dad raped me in my sleep when visiting our apartment years ago. I thought my son was my husband’s son. My husband later told me what happened to me that night.
I went to sleep, and my husband let that person into our apartment to hang out. At some point, the guy found his way to our bedroom where I was already asleep, because I had to go to work the next morning. Apparently, my sort of situation isn’t that rare.