Giving the benefit of the doubt, my guess is that he probably thinks that it's better having them under his watch than letting them loose where they can cause more damage. Just a thought...
Fr. Abraham was sent to a monastery by the sspx, in accordance with canon law and Church teachings. Fr. Abraham refused, instead agreeing to live with b. Williamson. B. Williamson, contrary to canon law, allows Fr. Abraham access to the public.
B. Williamson chose to accept pervert seminarians and then ordain them against proof and canon law.
If b. Williamson had never accepted them, they would not be pervert priests, at least not ordained by the sspx, so no watching would be required, and no children would have been harmed.
This is what gives me pause.