As executor of the estate Lee was duty-bound to conform to the wishes stated in the will. Even at that he attempted to extend the duration before eventually manumitting the slaves.
In trying to make a point, you continue to cherry-pick items out of context. You show enough of a knowledge of history, that you must certainly be aware that it was a matter of some concern among the Virginia gentry, over generations, how if one would free one's servants, how to go about it in a manner that would protect those servants, many of whom were actually loved, from the absolute nightmare that would result from manumission by decree during "Reconstruction."
If you had more respect for the honorable intentions of your fellow Americans, you might have a little better understanding of the very complex dynamics involved in the subject matter.
It is no small matter to toss the equivalent of many hundreds of thousands of dollars away. The wonder is that many people did it anyway.
If it takes fifty $20.00 gold pieces to equal a thousand dollars, and if gold is currently ~$1,200/ounce, then if a slave cost $1,000.00 in the money of 1860, that makes the manumission of each one equal to $60,000.00 in today's dollars.
The moral hazard here is the belief that human life can be equivalent to money. Again, this is a consequence of the Muslim religion, not the Christian one.