I think it should be banned but I don't necessarily think it NEEDS to be, there's a lot of other places where you can watch content that contains sexual content, not just on TV. It's everywhere, on HBO, video games, TV commercials, music, magazines, clothing, even toys. When I was young we were told never to look at a woman's chest or look places where you shouldn't be looking. Now when you go to a trusted adult that's the same gender as you they encourage you to be sexually attracted to people even though you don't want to and that's not okay. I have girls going around my school wearing clothes to the point where it's just as visual as wearing lingerie and no one's doing anything about it.
I became sexually attracted to things before I even knew what sex was, I learned what it meant not even 4 years ago because no one would tell me what it means, they'd just talked about it and I'm getting to the point where I'm just sick of it, it doesn't interest me anymore. Kids these days, the first thing that comes to mind when they're interested in something, is TV. If you're family likes to watch popular reality shows such as Big Brother, Survivor, and so on, you're going to notice some things.
People have different tastes, not everyone is going to be entitled to something just because a majority of society is.
TL;DR: "Why is Rap the most popular music genre and not Alternative?"
Sexual content doesn't need to be banned from television. Parents can block out certain channels from the view of children. Otherwise, sexual content will be removed from television only when the demand for such content wanes enough to make it too expensive to air when advertising revenue evaporates. When supply and demand ebb and flow, sexual content will adjust just like any other business.
Sexual content should not be banned by any media, not ones meant for consenting adults. Sex is apart of life, just like violence, just like cursing. Why should entertainment be void of any sense of reality? Because we want to run away from reality? Well, we should not and nor should we allow others to try to do so.