I have never once seen an ounce of hostility toward legal immigrants in my life.
I have, many times. And i would be surprised if you actually haven't. A lot of it takes the form of racism. I've heard people told "go back to ________". There are numerous immigrant small business owners who suffer abuse solely because they are (or are perceived to be) not native americans. The stereotype is Korean store owners in non Korean communities, who are purportedly prime targets, especially when things start to go bad.