Because intelligence tests were used to deny black votes in the reconstruction south. There are a variety of tricks that they’ve used from just giving harder tests to black people to giving tests that prioritize knowledge more common in white cultural experiences. And that’s not touching on the language issue as a means to deny immigrant votes

I know there's no hard and fast solution. Education? But that will take time. Encouraging people to vote? But if we let all the fascists get away with it they'll get in. Back in the 70s when I worked in a factory the hard line socialists always had a good turnout and got the vote at Union meetings etc. Those that were of a different opinion got shouted down so stopped going. The hardliners won.

Difficult times ahead.