My opinions here apply mostly to black/white relations, since the problem blacks are citizens where as the majority of problem hispanics are not and illegal immigration is a subject for another thread.
A couple thoughts that have occurred to me in recent years beyond the wildly disproportionate rate of crime among blacks locally.
1- The so called "racists" of the segregationist movement, that opposed the civil rights movement were primarily Southerners who lived in areas with fairly large black populations. They were familiar with blacks, they had daily contact with them, and awareness of how they conducted themselves in their own community. On the other hand, the pro civil rights whites were generally left leaning/socialist Northern college students who's only experience with blacks was watching "Amos and Andy" or "I Spy".
2- The opponents of Civil rights made certain predictions, such as Margret Sanger's ( founder of the eugenics program known as "Planned Parenthood" ) prediction that they would "out breed the more productive white race". many of these predictions have in fact been proven correct. As an example I will cite Whitey Bulger's home town of South Boston.
In 1971 Southie was all white and pretty much all Irish, the crime rate was so low people did not need to lock their doors, streets were safe, and homes and businesses were well maintained. In 1972 the Ma. legislature, dominated by outsiders who did not have to live there, mandated a busing program to "integrate" Boston's schools by busing black students into Southie. Opponents said that crime and violence would sky rocket to the levels of black neighborhoods like Roxbury, property values and "quality of life" would plummet, and Southie would lose it's distinct character as "a good place to live". The resistance was strongly supported by then Senate President Billy Bulger, and future Boston mayor Ray Flynn, both of whom were born , raised, and still lived in Southie. 40 years later, Southie is just as they predicted, a blighted, crime infested 3rd world sh!t hole.
In city after city across America opponents of Racial integration, accurately predicted "White flight, , decreasing property values and tax revenue, coupled with increased taxes ,crime, poverty, and demand for social services.
These are not opinions, these are documented historical trends that follow the scientific principle of repeated results of the same as actions.
It makes one stop and think that perhaps the principle of "separate but equal" had some merit.