Crime is only one element of what I view as how illegal immigrants have negatively impacted the region.
I don't know what the crime statistics are, but for a minority group, it does appear based on watching the news that a disproportionate number of crimes are committed by the Mexicans here.
NWA was not a crime free utopia before, but it decidedly did NOT have a hint of a gang problem, or any neighborhoods which were notorious for crime. A few older areas of a few towns are getting reputations for criminal activity.
Crime increases with population, that is a given. What is important to note is the RATE of crime per 100k residents. If I were going to bet, I'd bet that the crime RATE is higher among our illegal population than the general population. Whether that is a function of poverty or a function of not having ties to the community due to their status, or a cultural difference is open for discussion.
I predict that Springdale schools will decline in the future. I have heard stories of several families (white) moving to PG and Farmington and other areas because they were tired of sending their kids, mostly elementary school aged, to majority hispanic schools where half the day was spent overcoming language barriers. One can't blame parents for doing what is in the best interests of their children.
Legal immigrant children do not negatively impact schools in the same fashion. Legal immigration is at a controlled pace. The parents (and children, if they are born and immigrate) learn English and get educated about our laws, our history and our society. I grew up with several Asian immigrant kids whose families did it legally and they were almost without exception very good students and fully assimilated in an otherwise majority white school.
Another impact is the cultural differences. Not all cultural variety is positive. Having been to Mexico a few times, I have seen the general norms there are far different from what Americans expect in living standards, etc. Again, having Mexican immigrants here wouldn't be such an issue if the pace of their arrival was controlled and orderly, allowing for assimilation. Unfortunately they have arrived so rapidly that they are maintaining their norms in many of the areas where they have congregated. I do not wish to live in Mexico, therefore I am entitled to protest when I see my country being turned into Mexico. There's nothing racist about it. There IS something decidedly racist about race-centered groups like La Raza and LULAC.
Bottom line is the immigrants are being exploited, and middle class taxpayers are being exploited to pay for their healthcare, their children's education and even public assistance. In the process, we are seeing areas decline as our norms are exchanged for those of a third world country to the south. Whats sickening is that it is all in the name of profit for the rich few.
The illegals are better off here, but I'd argue that many of us who were here first are not improved by their presence in our communities, but rather harmed in several quantifiable ways.
That reality does create resentment, and it also encourages racism.
I don't think you'd see as much discontent if the Mexicans were coming here through the normal legal processes and obeying our laws from the get-go.