That is a top-level category and should not be used on person profiles.
The relevant subcategory (https://www.wikitree.com/wiki/Category:Slave_Owners_in_America; you may want to bookmark this category if you will need the subcategories for other profiles) is also a top-level category, so you should use its subcategory, https://www.wikitree.com/wiki/Category:North_Carolina_Slave_Owners, or a relevant subcategory on the referenced profile.
You basically work down the category hierarchy until you find an appropriate subcategory that is not top level.
edit: added italic text