Jeffersonian Olympics (CW: Slavery, racism, white supremacy)

[dukealien]

“Jeffersonian Gymnastics”

We hold these truths to be self-evident:
That Colored folk lack our white endowment.  perhaps em-dash here instead of period
Inferior in body and in mind,
Best housed apart, as Nature has assigned.
Liberty's tree is washed in tyrants’ blood,
While slaves wear lashes, as before the Flood.  Good changes here!  Perhaps "bear lashes" or if it's "wear," something to do with chains?

Though I proclaim all men to be my equal,
Yet my own child is dark, skin like treacle.  perhaps "her skin like..." to fill in the meter
I tremble, for God may be stern and just,
Yet trust He’ll wink at my familiar lust.
We share blood, but my soul I don't observe;  good try, but the inversion says this line isn't there yet
To own them is the justice I deserve.  I wonder if this could be "privilege" rather than "justice"

Some say I preach liberty whilst holding chains,
But they just lack my noble white man’s brains.
They say my words were light, my deeds darkness,  a word between "deeds" and "darkness" - 
That I sold fellow men to labour's harness.  how about "in" rather than "to" - forms a picture?
Freedom spoke through me: The voice of others--  how would this look with a semicolon after "me" and a question mark at the end?
Bought by the silence of my brothers.

In Fate's book is writ, "all men are to be freed;"  pardon the rewrite, but "In Fate's book it is writ, "men must be freed"
So let my chattel work, or let them bleed.  tempted to say "But" here, but to dark-Jefferson, his slaves weren't men.  So stet.

Much improved - admire your inventive changes; suggestions above are just that (hesitate to interfere by rewriting).  There are some lines which don't need any punctuation at the end, even a comma, since the next is a natural continuation of the sentence; these work better when that next line is not capitalized.

Only suggestion on meter is to read your poem out loud and notice where you have to backtrack or break rhythm.