I confirm that I, as a "player," also keep the audio turned off, so I don't pay much attention to whether a game has it or not.
However, it's true that both here and on itch.io, a lot of people ask for it. My main issue with audio is that syncing it with the sex scenes is a hassle—it would take me much more time for development, and I’d end up extending the development timeline further.
You notice there’s no audio, but in this type of game, how many people actually leave it "on"? If I were to include it, it would probably be more about the "click" sounds and text effects, along with some background music, rather than syncing it specifically with the scenes.