The point is that white voters were given a pass. Look up the origin of the term "Grandfather Clause." Passed in seven southern states after the end of Reconstruction, it stated that voters whose grandfathers were eligible to vote before 1867 were exempt from taking the test.
Repeat. There is nothing wrong with literacy tests for voters. It's all in how they are administered. For example, in New England the literacy tests were handled with fairness, but they were given in English. If you did not speak English, you could not pass the test. Which come to think of it, wasn't all that bad an idea.
The Republican Party must do something about vote fraud, part of which is last-minute registrations of a highly fraudulent nature. A fair literacy test, administered well before elections, with preparation materials and ample opportunity for do-overs would certainly help give us a more informed and honest electorate.
Doing away with Literacy Testing because it was abused in the Democrat South is a classic case of "Throwing Baby Out with the Bath Water."
From when did you pull out that little gem? I can only go with my experience and talking to a few other people at the college I was at in Alabama in 1964, but all of us had to take the test and all of us were white.