Well you see, I would hate to live in a world where it became socially acceptable to talk about human sexuality
I think it is good to be able to talk about it to your close friends / family
But I'm already disgusted when I hear coworkers talk about porn or their (most of the time imaginary) sexual life.
I think it is a very personal subject, and maybe I'm wrong, but I feel like you'd get less freedom in your sexual life if everybody was talking openly about it. Part of why I think that way is: people have weird fetishes for example, you could think in a society where you can talk openly about sex and you sexual life you could talk about your weird fetish, but I don't think that's the case, only "popular" fetishes / sexual preferences would be discussed, and "weird" fetishes / sexual preferences would be seen as degenerate.
Again this is my opinion, maybe I'm wrong, but I would definitely not want to talk openly about sex with random people.