Well .. is it though?
What if everything is so blissful and boring in the future that people intentionally torture themselves for decades at a time by experiencing "Earth-sim" so that they can build character / enjoy the utopia they've created? Or maybe this simulation is the rehabilitation track for criminals? There are a number of reasons to "suffer" and suffering shouldn't be cast out as unethical because we don't like it in the current context.
Please do provide some reasons why raping a day-old newborn infant wouldn't be considered unethical.
you are creating new lives that are capable of experiencing suffering, and who inevitably will at times
Hence my statement: if you had reason to believe there was a sufficient likelihood of a sufficiently negative outcome.
I've always thought this part was, by far, the most likely. It would be unethical to create a simulation in which the simulated beings were sophisticated enough to be self-aware and capable of significant suffering. It's the same thing that's caused me to shift from "I don't believe in god" to "I believe there probably isn't a god". For example, infants have been raped in Africa due to the virgin cleansing myth, and every year thousands of people kill themselves due to unmanageable misery. Not to mention the way that so many people die of "natural" causes, e.g. drowning in their own phlegm only to be revived by hospital staff for another go-around.