Same in the UK, and for what looks like a very good reason: to attack the pimps instead of the prostitures. But the unintended consequence (maybe not unintended) is that people who organise sex parties, like the famous Cynthia Payne, are only safe if they can prove they're not making a penny out of it.
They are trying to do this by the back door here, by trying to making it a criminal offence to buy sex with someone who is being coerced into it. The excuse being that some prostitutes are trafficked from eastern Europe and enslaved by gangs. This undoubtedly happens, though it appears that the people promoting the law have greatly exagerated the numbers (it turns out that the enormous figure they often quote was arrived at by taking some policeman's blind guess at the number there might be in a particular notorious red light district, and multiplying it by everything the author of the study could think of), and it is undoubtedly a very bad thing.Some parties want to change this, to get at prostitution, but from another angle. They want it to be illegal to buy sex.
But there is already a raft of laws on the books for fighting traficking, if the police could be bothered to use them, and making someone criminally liable for unknowingly taking part in an illegal act is bad law. It is transparently obvious that the aim is to scare men off prostitutes completely.
The backers are the sort of sex-haters who give feminists a bad name, and blank out any discussion of how to make prostitution safer; they talk of prostitutes as if they were too stupid or childish to know better and need to be saved whether they want it or not. They show blatant contempt for the sex workers' unions, and if anyone speaks up to say "I'm a prostitute and it's not all bad, I chose to do it and all I want from the law is the same protection as any worker," she gets called a liar and a slut in equal measure.
Is my opinion clear?