@mysteryman,
You fail to understand the fact that "Democrat" and "Republican" are just labels that may have little meaning. What you need to do is to look at political ideology (in this case, liberalism and conservatism) and learn what the record is of each ideological movement.
You also seem to be ignoring the fact that there has been a significant change in both political parties in the last 40 years. In the 1960s, both parties had a left wing and a right wing. In other words, there were conservatives and liberals in both parties. By the time Nixon was elected President, both parties had begun to undergo a polarization in which the Democrats lost most of their conservatives and the Republicans lost most of their liberals. Today both parties consist of only one "wing."
The record of political conservatism with regard to Jim Crow, under which I grew up, is absolutely pathetic! Just about all leading conservatives
defended racial discrimination against black Americans! William Buckley, for example, along with all the other leading conservatives, condemned the landmark Supreme Court ruling
Brown vs. Board of Education. (Incidentally, Brown was a case of busing for the purpose of maintaining segregation in the public schools. Buckley and all the other conservatives had no problem with this. But during the 1970s they opposed busing to bring about integration in the schools.
What hypocrisy!) At the same time, conservatives relentlessly attacked the civil rights movement. They hated Martin Luther King, Jr.! Ronald Reagan had a fine civil rights record: He opposed the 1964 Civil Rights Act, the Voting Rights Act in 1965, the first renewal of the Voting Rights Act in 1970, and the second renewal in 1975. I'm a white guy; but if I had hated blacks, I would have loved Reagan! I could go on and on and on, pointing out the shameful record of political conservatism on the issue of civil rights.
There were Republicans during the 1960s who supported civil rights. But most of them were moderate to liberal -- the so-called Rockefeller Republicans, who were
despised by the William Buckley, Barry Goldwater, Phylis Schafly conservatives. The white Southern so-called Democrats were conservatives. The leadership of the Republican Party and individuals such as Lee Atwater invited the unrepentant segregationists into the Republican Party. (Incidentally, when David Duke was elected to the Louisiana state legislature, that beacon of morality named Newt Gingrich publicly declared that Duke would be welcomed into the Republican Party after a few years just as long as he watched what he
said. Good public relations, no doubt.

) My wife, who is now in her early sixties, had been a Republican ever since she was a teenager. But she left her party (to become an independent, not a Democrat) because she was sick and tired of all the unrepentant one-time segregationists into her party. There are even white Republicans today who call Lincoln ( the founder of their party) a Marxist or say that he deserved to be assassinated!
Oh, and lately . . . guess what. The Supreme Court Justices who voted to rip the guts out of the Voting Rights Act
are all conservative Republicans. There's nothing noble about it. It's all part of the minority voter suppression drive by which the Republicans hope will ensure their power until Doomsday.
As I've already said before, I'm not a Democrat, either. I'm not able to support them because of their stances on two major issues which I don't care to discuss because most people apparently are unable to maintain any level of civility in an online forum. I've lost my temper a few times myself. For me to support either party, I would have to violate my conscience.
So, I had resolved to stay away from any controversial political or religious issue; but I couldn't resist commenting on this garbage. I get fed up with OPs such as this one (entitled "The Democratic Party's Long and Shameful History of Bigotry") which are nothing less than exercises in intellectual dishonesty that is so blatant that even Herr Goebbels would be scandalized!
By the way, Rush Limbaugh recently claimed that the 1964 Civil Rights Act never would have passed without the support of the conservative Republican Senators. A COMPLETE DAMNABLE LIE! Almost all of the Republican Senators who voted for the Civil Rights Act in 1964 were Rockefeller Republican -- who, as I said before, were DESPISED by the conservatives in their party. Limbaugh is too much of a coward to admit this fact. But he hopes the gullible will swallow his lies, and I fear he may be right in that respect. In the meantime, this intellectual dishonesty, this Orwellian rewrite of history (make that outright falsification) is the most blatant I've ever seen in the politics of this country since I became interested in national politics in 1969. Goebbels would, indeed, be quite impressed by American's own use of the Big Lie technique.