It did not actually include the right to own a human being. It did prevent any slave import bans before 1808 (And a ban on importation did take effect then https://en.wikipedia.org/wiki/Act_Prohibiting_Importation_of_Slaves). For the purposes of representation, it did count “three fifths of all other persons” (Having previously mentioned “free Persons” and “Indians not taxed”).
There is no mention of a “right” to own slaves, and the only part of the Constitution that might be construed to grant that right is the 9th Amendment,
“The enumeration in the Constitution, of certain rights, shall not be construed to deny or disparage others retained by the people.”
And it doesn’t say anything about owning slaves. In fact, the 9th amendment works better as an argument against slavery (even without the 13th amendment) that it does as an argument for slavery.