@Remus2It's not that one party or the other has any inherent whatever.
BUT the people with certain inherent traits HAVE switched party loyalties as those traits moved.
The modern Democratic stance came about unwillingly.
In 1908, an argument over, if I recall right - gold vs silver vs other standards. The Democratic candidate who was also the lawyer that later won the trial case against teaching evolution... he figured he could win by angling his position as good for labor.
He lost, but the Dems took on a pro-labor platform.
Unions at the time were White Only. Companies would hire Blacks and Hispanics as 'scabs' to work when there was a strike.
The Dems spent a good few decades trying to fight 'scabs' until somebody pointed out that 'why don't we let these folks join the union?' and the Southern Dems lots the argument against it.
- So that was how the Dems became first a labor party, and later a civil rights party. It was always a marriage of convenience.
Over time with passing generations the people who were naturally attracted to one of both of those stances became Dems, and the people who were not left and joined the Republicans.
Thurmond was part of that final generation of 'Dixie-crats'.
Except the Dems still have 2 Dixie-crats in the Senate right now so... the transition isn't 100%.
Plus Since Clinton, the Dems have been moving away from labor.
So Working Class whites were left "in the wind", and the Republicans saw the opportunity to tell them the fault for their troubles was minorities, gays, and immigrants - and not automation, lack of infrastructure, and poorly funded schools.
The Dems were right to fully embrace civil rights and work hard to chase out all their Dixie-crats. But they were seriously stupid to abandon labor.
One reason Democratic coalitions always have so much trouble is that their historic two platforms were united by need and never really brought together well. Democrats build coalitions of people that each have an issue - but are not willing to be second or third in line to having their issue addressed.
Republicans build around charismatic figures who tell people what to be against. Dissent takes a second seat more easily.