I get this question a lot from people who haven't been to Thailand: "I hear that there is a thriving sex trade in Thailand. What about it?"
The sex trade is there, but it's overblown by western media. Most Thais are embarrassed by this reputation which is geographically centered around two cities-- about 5% of Bangkok and 20% of Pattaya, a seaside resort city. It continues because of the power of the mafia over law-enforcement, not unlike parts of Italy (Sicily) or modern-day Russia. In fact, it's the infusion of the Russian mafia into Pattaya which has given a recent boost to this social problem.
Despite the problem, it's important to realize it's geographical size and activity are limited to real estate smaller Las Vegas, Reno, or seedy areas of New York City or Chicago. In fact, it's considerably eclipsed by those USA venues of sleaze.
Yes, it's there, it's wrong and it is a blight on the Thai reputation. But, just as we wouldn't judge all Americans by what goes on at the street corners of Times Square or at the legal brothels of Nevada, we shouldn't similarly judge the Thais.
In a sense, the reputation of Thailand is being held hostage by western "news-tainment." I've seen some of the documentaries, which are quite "hyped" around a core of truth. However, for every sensational documentary on Thailand's sex trade, you could produce 100 documentaries on family-centered village life, with 1950's American morality--which is the real Thai scene. On the other hand, the latter type of documentary just doesn't pump up the viewer numbers for those Nielsen ratings in the west, of course.
Hope that helps balance the picture! Better yet, please come to Thailand and see for yourself. For most places outside of the venues mentioned above, it will be like you've been transported back to 1950's or 1960's Anytown, USA in terms of morality, human relations, and social interaction.