If there's a neighborhood that for various reasons is occupied predominantly by Black people,

and if (as your article points out) a substantial percentage of the housing there is rental property,

and if the majority of rental property owners are White or large corporations / banks (which normally means White),

then it is in the interest of the White owners of Black rental housing to keep property prices depressed, because the White property owners will pay lower property taxes.

Black people who own property in these neighborhoods will not see their property values increase over time as would White people who own property in predominantly White neighborhoods or in gentrified (i.e. White) neighborhoods, and thus the wealth gap between Whites and Blacks will increase proportionately.

Keeping these housing prices cheap also makes it easier for Whites to gentrify Black neighborhoods, forcing Black residents into inferior homes / locations that are just as expensive as the properties that were bought out from under them--upward mobility for White homeowners, downward mobility for Black homeowners.