It's really interesting how much effort had to be undertaken by lawmakers in so many states in order to prohibit something that clearly was going on. A whole apparatus of legislation arose to prohibit it, and in a way that runs so much against the grain of the democratic ethos. The free choice of the person you want to marry seems to be a pretty basic human right. From that angle, it does indeed seem that the core of the fear of racial integration is miscegenation, and that everything else surrounding it is protecting that core. President Truman famously asked that of a reporter.
Women are white women.
Which is something the last three decades of scholarship about black women has somewhat corrected and challenged. Even in South Africa, the legal prohibition on interracial marriage was short-lived. Only after World War II was interracial marriage prohibited in South Africa, and that lasted 40 years. Whereas prohibition of interracial marriage in the United States is pretty much the whole history of the country until 1967. That's a very dramatic difference.