Why are African American voters relatively monolithic

[Oldiesfreak1854]

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."

[Oldiesfreak1854]

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.

idk, because if racism is an issue in this, then blacks may be wary/not trusting the states/regions and people/descendants of racist people, who are all more or less now represented by Republicans. Republicans are the party of the South now, and some even going back as far as Eisenhower, all those racist Democrats started voting either Republican or 3rd party for president since Dwight or Goldwater, with just one break for Carter and a few misc. states breaking for Clinton due to his regional origins.

And you're acting like the entire Democratic party was one big racist, segregationist jamboree. It wasn't like that. Whether anyone likes it or not, Republicans now represent the old confederacy and consist of people who were either raised by, or are, old racist assholes. I'm not even saying most current Republicans are racist - Definitely not. But, especially when you consider states like Alabama - you can't honestly believe all those old Alabama folks were, what, airlifted out of there and replaced by non-racists?, or something.

Finally, let's not forget dear old Ronald Reagan's (Republican) campaign announcement speech in Mississippi, where he talked about the virtues of state's rights (cough cough segregation cough), only miles away from where civil rights workers were killed in 1964.

That bullsh**t is what the Republican party accepted and encouraged in order to claw back power in the federal government/state legislatures

https://en.wikipedia.org/wiki/Reagan's_Neshoba_County_Fair_%22states'_rights%22_speech

Oh boy...where to begin?

Ike campaigned as a strong supporter of civil rights, and his record as president shows that, from the appointment of Earl Warren as Chief Justice, the Civil Rights Acts of 1957 and 1960, and his sending of federal marshals to Little Rock Central.  Stevenson was the one who had a segregationist running mate in 1952 (John Sparkman).  Democrats may not have been uniformly racist or segregationist by the 50s and 60s, but Democrat presidents throughout the 20th century dragged their feet on civil rights in an attempt to appease the Southern segregationist wing.  When Truman and Johnson tried to move forward, the segregationists revolted and formed a third party (the Dixiecrats in 1948 and the American Independent party in 1968).   

Most of the segregationists in the Democratic party NEVER joined the GOP.  They either died, renounced racism (e.g. George Wallace), and/or retired from politics.  Robert Byrd, the former Klansman who filibustered against the Civil Rights Act in 1964, was still a Democrat when he died in 2010.  Fritz Hollings, the former South Carolina governor who first flew the Confederate flag over the state Capitol, opposed the integration of lunch counters, and voted against confirming Thurgood Marshall to the Supreme Court, was still a Democrat in 2004.  Yes, you are right that the segregationists did split ticket to vote for Goldwater in 1964, but after that, most of them went straight back to the Democrats.  The few Dixiecrats who did join the GOP did so for political expediency--they were seeking to challenge incumbent Democrats or wanted to throw their support behind Goldwater.  At the state and local level, Dems continued to dominate much of the South until the 80s and 90s.  (Case in point: Mississippi Democrats did not lose control of the state legislature until 2011, and Georgia's first post-Reconstruction GOP governor was not elected until 2002.)

And as for the Reagan "states' rights" issue, this was long after the big battles of the civil rights movement had ended (CRA, VRA, etc.)  States' rights was not always used as a code for segregation, and even when it was, it was abused and distorted by the Dixiecrats.  You can give states all the rights you want now, and Jim Crow is never coming back (good riddance).  In his personal life, Reagan proved himself to be anything but a racist.  When he played football at Eureka College, he refused to stay in a segregated hotel with the team and took one of his black teammates to stay with his parents.  This story was confirmed by a left-wing reported and even published by the NYT.