Trying to wrap my head around this, I'll propose that this society has 'freedom of intercourse'. Stopping someone by force from having sex with you would be as improper as stopping them by force from talking to you, even if you didn't like it. Walking away might be acceptable but considered generally impolite. People who have nonconsenual sex frequently would be stigmatized and avoided as annoying people are today, but

Today nonconsenual sex is bundled with violence, fear of violence, and expectations of personal space. If the impossible possible culture is such that everyone expects their genitals to be part of the social space instead of their personal space, then no great sense of emotional violation will be felt even if the social interaction is unwanted.

They likely view the prohibition as just as shortsighted as we would view restrictions on 'free expression'.

Very good of Eliezer to let us identify with the humans before delivering further culture shocks. I suspect that the next installment will have further human weirdness.