The effect of the law is mainly on public morals.

I see. Oh dear, there is public morals again, when I thought we were rid of it.

So that law, which (at least ostensibly) intended to eliminate an extremely exploitative profession, is a complete failure. Public morals don't interest me, and public morals don't improve the situation of the prostitutes either. Guys who buy sex aren't the issue for me, only poverty that makes people do jobs that are degrading is the issue. Giving residence permits and working permits and proper jobs to the women will reduce the pimps' profits. Encouraging the women to give evidence will increase the pimps' risk. This approach won't find the approval of the xenophobian mainstream, though. It's poison for getting re-elected.