If you ban it, you drive it underground
Ah, the apologists' get out.
We can't ban things because people will do them anyway.
So instead of spending our resources policing what is wrong, we give it The imprimatur of legalisation and then spend time making sure people are exploited "safely".
By that argument we should legalise slavery, rather than drive it underground where slaves are at increased risk.
Let's have it all above board and spend our time regulating it so the slaves are safe.
This will, of course, be massively beneficial to the slave owners and traders.
But that's all OK. Only safety matters. As long as people are "safe" it doesn't matter how shit their lives are.