How could Congress agree to sign a document stating that all men are created equal and not immediately outlaw the enslavement of africans

Congress viewed black people as not being human, and since the phrase "All men are created equal" only applied to what they meant when they wrote "men", slaves were not freed.

slaves were labled as implements or property and didn't have rights

Explanation:

slave owners declared slaves as tools rather than humans

in the declaration of independence, thomas jefferson announced that every human being has “certain unalienable rights,” among which are those to “life, liberty, and the pursuit of " hope i