These restrictions and laws placed on African Americans, particularly during the Jim Crow era, did not allow representation from black communities in voting. Voter suppression of blacks caused populations to be unequally represented in the demographics of a town, county, state, or any other voting poll. White voters were trying to disallow for any representation the black communities may have, and as a direct result belittle them as people.
The stock market cash led many people to withdraw their deposits/take out loans from the banks. And because people could not pay the banks back for this, it ultimately lead to banks not having enough money to function.