Now we're going to play the "Questionizer" game. The game starts with a
question related to Lesson 20. The first student to respond to the initial
question will answer it and will then post a new question about the content of
Lesson 20. The next student will answer the most recent question and will then
post another question. The process repeats until every student answers and
writes one question, creating a long chain of questions and answers in one
single post!
Initial Question: The Ku Klux Klan actively terrorized many individuals
during Reconstruction, including white Republicacs, politically active
African Americans, and any African Americans whom they regarded as
too "economically successful."
Why do you suppose this group chose to target economically successful
African Americans?
No

The Ku Klux Klan realized that it would be harder to keep African Americans down if they were economically successful because they would be able to influence things more with money on their side. They therefore targeted them so that African Americans would remain poor and easier to oppress.

Other reasons included:

They would employ other African Americans - Economically successful African Americans might employ others as well which would make more African Americans successful which would reduce the number of Blacks that could be discriminated against.
To kill inspiration - Discrimination against people works better when they feel they have no hope of getting out of their predicament. Economically successful African Americans showed that there was still hope so in attacking them, the Ku Klux Klan wanted African Americans to remain hopeless and disenfranchised.