the locals who really want to do those things have long moved out of the country. those who choose to remain here enthusiastically enforce the order of the country. caning and hanging continue to enjoy popular support.
Don't come, if you like to partake in recreational drugs.
(Though plenty of expats usually just hop on a plane on the weekend and indulge in one of the surrounding countries. Drugs are no more legal there, but their governments are not as competent in enforcing their laws.)