There is this idea in our society that has been bred into us through the media, government schools and culture, where law must line up perfectly with traditions and social convention. If something is frowned upon or taboo, you can rest assured that there is someone out there who thinks that it should be illegal.
When a particular activity or behavior starts to bother people in the kinds of societies that we have today, all too often those people are very quick to suggest that the proper solution to this problem is to throw that person in a cage. That may sound kind of harsh, but that is exactly what you are advocating when you claim that something should be illegal.
In a world as delicate and complex as ours, does this really seem like a proper one size fits all solution for our social problems, especially those where there was no violence, theft or fraud involved? There is no dispute that violence, theft or fraud should be illegal because no one wants to get hurt, or robbed or ripped off.
However, when you start getting into nonviolent crimes where there has been no theft, is bringing aggression upon that person in the form of kidnap and imprisonment really going to make anyone safer? Furthermore, is this an ethical, humane or civilized way of treating nonviolent people?