Drug addicts affect nobody but themselves? Surely you aren't serious. They fuck up everything around them and immiserate everyone around them. It's very rare for a serious drug addict to not have committed a slew of other crimes during the course of their addiction. There's also a nice amount of overlap in drug abusers and sexual promiscuity.
BTW, selling sex is illegal. Morally, neither promiscuity nor drug abuse are things you'd hope for in friends, family, neighbors. Legally, sex serves a biological purpose, and is encouraged in monogamous couples, so it's impractical at best to investigate every sexual encounter to discover intent, but coercive sex, sex with minors who can't consent, sex in public, and prostitution are illegal. Drug abuse is a little more cut and dry, since it really serves no other purpose than being a drain on society. Promiscuous sex is also not a product being imported to wreck societies. There isn't any way to stop the flow of vaginas coming into the country, and everybody is already in possession of sex organs through no fault of their own.
I will say this though, skanks are really pushing hard to make their sleeping around a drain by demanding other pay for their birth control, wanting others to subsidize murdering their children, and demanding social acceptance of their sexual recklessness.