I am pretty sure you are mixing up the US Constitution (1787) with the Declaration of Independence. (1776.)
If you have evidence that 11 states were more concerned about slavery when they signed the Declaration of Independence (1776) than they were about their own freedom from England, I will be fascinated to look at it.
Now let's remember that Lincoln was referring to 1776 (Declaration of Independence) and not 1787. (Constitutional Convention.)
A: (No Response)
This likely means that whatever motivation you have, it would sound terribly silly and ridiculous if you actually let people know what it was.