"Black Wall Street" is a bit misleading, as it wasn't a regional or national banking and financial center. In an era when blacks weren't welcome in downtown Tulsa, it was a self-reliant community very similar to black business districts in Kansas City, Dallas, or Chicago. Tulsa's development had been more rapid than those cities, however, having enjoyed the rapid wealth from oilfield industries and finance. So Greenwood may have had more impressive business blocks than found in the Negro districts of other cities of Tulsa's size. I think the source you linked is on shaky ground with many of its assertions and assumptions.

A decade ago, for the Encyclopedia of American Urban History I tried to describe the Tulsa Race Riot succinctly and accurately:

African-Americans, hoping Oklahoma would be less overtly racist than the Deep South, had created a thriving business district along Greenwood Avenue by 1920. Though the new state had not directly inherited pre-Civil War notions about race, it quickly adopted Jim Crow laws and eventually became fertile ground for the revived Ku Klux Klan.

The arrest of a young black man on dubious assault charges June 1, 1921, set the stage for one of the nation’s worst race riots. Blacks, fearful that the jailed man would be lynched, approached the courthouse to find a large crowd of white men. Violence broke out and the white mob marched on the Greenwood district, indiscriminately shooting residents and setting fire to buildings. An official death toll of 36 is believed to be much higher, and some 35 blocks of businesses and homes were destroyed.

I relied on these general histories:

Vaughn-Roberson, Courtney Ann and Glen Vaugn-Roberson. City in the Osage Hills. Pruett Publishing Co. 1984.

Goble, Danney. Tulsa! Biography of the American City. Council Oak Books 1997.

However, a lot of research has been done on the incident in recent years, and there undoubtedly are now sources that explore the riot in much more depth, from primary sources.