Answer:
Right or wrong, opponents are concerned about the risks of market competition. They want native-born Americans to keep their jobs, and they don't want them to face wage cuts. Right or wrong, opponents are concerned about the fiscal burdens imposed by first-generation immigrants. Opponents are hostile to any group — national, ethnic, racial or religious — different from their own. Opponents are hostile to certain groups — Latinos and Muslims in particular.
The report finds that immigration has positive effects on economic growth — and doesn't hurt the employment or wages of native-born workers.