The answer doesn't address the assertion. Prostitution behind closed doors, where there aren't children, is still illegal. Solicitation for sex in a public park could be criminalized even if prostitution were legal, and it would address the cop's concern.
In addition, the project will examine laws against public lewdness, "which are routinely misused to persecute and prosecute people who participate in non-traditional forms of sexual expression.""I've seen firsthand how the misuse of these [public lewdness] laws has ruined the lives of gay and bisexual men," said Matt Foreman, executive director of the National Gay and Lesbian Task Force.
I don't know why the cop is explaining himself anyway. It's a crime, and his job is to arrest criminals. If people want to debate the legalization of prostitution, that's fine, but the cop will still need to do his job up until the day prostitution is legal. And, at that point, your second point will come into play; Blower and Homer and all the rest of these village people will have to follow certain guidelines if they wish to continue practicing their "craft."