What is all this talk about rehabilitation? The purpose of prison is to punish. A person steals, rapes, robs, peddles drugs, etc., is not sent to prison to learn valuable new job skills; but to forfiet years of personal freedom in a bad environment. Sometimes they might earn a GED, but that is because the state feels a person with a job in the end will have a better chance of contributing to society. In the end, most head back to prison because soceity (for better or worse) seldom will hire a released inmate.
Someone said you move sh!t from one place to another is still sh!t. True, but sometimes sh!t can be used for fertilizer. Occasionally the immigrant who has no job in the DR, does not speak English, has a rudimentary education, has no marketable skills, etc., can find work and become a productive citizen here. But the odds are stacked against them. Americans who are poor, undereducated, unskilled, and without reliable transportation will have difficulty finding productive jobs; and they speak English. So where does the Dominican immigrant find employment? No where. So they resort to crime (as do Americans in similar shoes).
Eventually those immigrants are punished in US prisons and returned to the DR. Now the Dominican Republic must deal with them. They are still poor, undereducated, unskilled but now speak two languages. If they cannot find a suitable job, they will again resort to criminal behavior. Basically nothing has changed in thier lives except they have learned English.