Because they've been brainwashed by Democrats into believing that they were the good guys in the civil rights movement and that the GOP is racist. Democrats have taken a century-plus of their racist history supporting slavery, the Confederacy, the KKK, and Jim Crow, and pinned it on Republicans, the party that abolished slavery and fought to end racial discrimination against blacks. And whenever someone dares to bring up these facts, they will resort to lies and excuses like, "Oh, well the Dixiecrats all joined the GOP after Johnson signed the Civil Rights Act,"(hello, Robert Byrd!?) or "Nixon and Reagan used racist dog whistles to win the Southern vote," or my favorite, "but Republicans were the liberals back then." I dare you to ask the average American, black or white, which party formed the KKK, passed Jim Crow laws, and supported slavery and the Confederacy during the Civil War. I bet at least 90% of them would say “Republicans.” Likewise, if you asked them which party was formed to end slavery, a similar percentage would say, “Democrats.” That’s how brilliant the left-wing Freaky Friday deception has been on race and civil rights.
Plus, Democrats are the party of entitlements, and they win the black vote by scaring them with smears about how Republicans are the party of evil, greedy rich people who want to privatize Social Security and leave poor blacks starving in alleys. It’s not that blacks are stupid; it’s that Democrats have done such a masterful job at keeping them in their fold with these scare tactics. The ads that the Missouri Democrats ran in 1998 warning that electing Republicans would lead to cross burnings and church bombings are a classic example of this. Democrats thrive on this sort of racial identity politics, and have from the very beginning of their party. The only difference is which race they're using. For most of their history, they were a white identity party; now they use non-white identity instead, teaching minorities to blame all their problems on "racist white people."
At the moment it's the Republicans passing repressive voting rights bills, it's republican appointed judges who are dismantling the voting rights act it's republicans but yeah the democrat party is the 'blame the white guy party'-if that makes you sleep better at night keep believing it, and we'll be more than happy when Hillary goes to the White House in November
