The perfect slave needs no shackles, he has been conditioned to think that he is free.
The perfect slave reasons away his slavery, by continuously arguing the degree of his enslavement.
The perfect slave defends the slave master, because the master lets him sit on his porch to keep an eye on the other slaves.
The perfect slave is so easily manipulated by his superstition, because the slave master understands the nature of man.
It is very simple: Give the slaves drama and diversion so they can easily be divided and conquered. Let them tear each other down, while they are being raped and pillaged by the slave master.
Let the slaves think they are in control by letting them vote for a new master.
Let them fight about their man made religion, their skin pigment, their sexuality, the degree of their slavery and their God complex.
Poison their food and water and then condition the slaves to believe that it is good for them. Take away everything that is natural, then condition the slaves to be unnatural.
Make the slaves sick, then offer them a cure. Flood their world with addiction, then make it illegal.
And the most important thing. Make sure you condition the slaves to immediately deny their slavery when it is pointed out to them.
That is your cue, reason it away.