It is simpler, if often appropriate, to condemn governments for their serial failures to successfully negotiate and interdict slavery and human trafficking. We would all do well to also understand that the reproduction of specific, known and well-defined classes of inequitable outcomes are not merely a consequence of corruption and failures of intelligence where these do indeed exist, they are in many ways the necessary legal fact upon which governments must anchor themselves for continuity of political tenure and functional self-validation.
It is, with or without incompetence or malevolent intent, the essence of a regulatory framework to inadvertently reproduce precisely the problems that it aspires to resolve. Prohibition has failed for precisely this reason – the failure reproduces the assumptions and actions that generate the problems for which the regulatory intent and legal prescription is so poorly equipped to negotiate. Government as regulator does not always fail but when it does, it does so in ways that reaffirm the significance of a continuing presence of that regulatory framework.
The TL;DR: governance of such serious problems fails because governments reproduce themselves through the problems by which they reflexively self-validate. Few in government are clever enough to either understand this or to act upon it and so the spiral of human catastrophe (indicated in the video) just keeps on keeping on reproducing itself.