Outlineing the conditions of Black people in the 13 colonies

The second excerpt of the article “The Idea of America”, published by Nikole Hannah-Jones in the New York Times on August 14th, 2019, it exposes the double standards of the American colonists, who blamed the British colonials for the cruel crime of slavery they had committed when declaring independence andwhile demanding equal rights for everyone.

(1) The "it" is ungrammatical, because the subject ("[t]he second excerpt") has already been introduced in the same sentence.
(2) I'd suggest replacing "and" with "while". Since we're talking about double standards here, it's better to make clear that engaging slavery and demanding equal rights were things the British colonials did simultaneously. "And" might imply that the two acts were independent of each other.

ThoughDespite them being an actual human beings, enslavers passed a set of laws resultvoking their human status.

(1) You should add a "them", because the way you wrote it implies that the enslavers are the ones who are "actual human beings". The "them" establishes that you're referring to the Black people instead.
(2) It should be "actual human beings" instead of "an actual human being", since "Black people" is plural.
(3) revoke: officially cancel (a decree, decision, or promise).

They were denied marriage and the keeping of their children eitheras well.

"keeping" by itself would be a verb. "the keeping of" establishes it as a noun.

In order to earn the most profit for their owners, they would sell what they didn’t wantneed.

"want" is okay, but allow me to suggest "need". "want" suggests that the slaves still had some choice over what they could sell.

In the first paragraph, the author critiqucises Thomas Jefferson.

critique: a detailed analysis and assessment of something, especially a literary, philosophical, or political theory.
criticise: indicate the faults of (someone or something) in a disapproving way.

In the following,above conditions, the Black people endured during the era of slavery.

It should be "above", not "following", since you outlined said conditions above, not below.

The second excerpt of the article “The Idea of America”, published by Nikole Hannah-Jones in the New York Times on August 14th, 2019, it exposes the double standards of the American colonists, who blamed the British colonials for the cruel crime of slavery they had committed when declaring independence and demanding equal rights for everyone.

The situation of the Bblack people in the colonies is described terribly.

ThoughDespite being an actual human being, enslaves passed a set of laws resulting in their human status.

They were also denied marriage and keeping their children either.

In order to earn the most profit for their owners, they would sell what they didn’t want to.

In tThe following, conditions the Bwere what black people endured during the era of slavery.

Slaves were revoked of their human status, enabling the opportunity for their owners to trade, buy and sell them.

I think you may have accidentally repeated yourself.