Give Me Liberty, or Give Me Hobbes

Hobbes, being a staunch materialist, defines liberty in the beginning of Chapter XXI as "the absence of opposition (by opposition, I mean external impediments of motion)..." He also states that fear and liberty are consistent, as are necessity and liberty. Just because one acts out of fear or necessity does not mean their liberty has been impeded. If a man were required by the state to hand over all he owned to the government or else be hanged, he is nevertheless free to choose either course of action. He fears death, but he is at liberty to resist the order and be killed for it. The same goes for necessity. If one absolutely needs to drink water or they will die of dehydration, they still have complete liberty to drink or not to. If they were held down and water poured down their throat, they would no longer be free. As long as no external forces act upon the body, liberty is retained. This becomes more interesting when you look at internal forces that may not be consistent with the will. Involuntary movement disorders that cause one to move against their will might seem to us to be impeding liberty, but Hobbes would see this as a deficiency in strength and, not interfering with will or liberty. Illnesses due to their internal nature, do not interfere with freedom or liberty, only with "strength and wit". 

The implications all of this has in Hobbes' envisioned society are monumental. It allows for totalitarianism on the basis that is does not interfere with the freedom of mankind, granted the government doesn't physically impede the motion of anybody. It offers a complete justification of the institution of slavery, again as long as iron chains or restraints are not used. So are slaves really free? Is it simply fear and apparent necessity that keeps them in bondage? If so, Hobbes would agree their liberty is still intact.