If you have the money to pay 1000 bucks a night, why do you go somewhere? Tours in Thailand became so widespread because there are no stringent laws for sexual harassment and a lot of cheap prostitutes.
Tours in Thailand became so famous because what is not legal in the western nations is legal there. Also, most of the girls trafficked in to the sex trade are from the minority hill tribes. The Thai government is not much concerned about them, as long as the majority ethnic Thais are able to make money.
Tours in Thailand are not advertised as sexy, they travel so they are completely legal in all countries. Another thing is how the tourists behave on tour, but this is the problem of Thailand. They are quite happy with everything.