I am an activist journalist and I went to Mexico 3 years ago to learn Spanish, it was a total culture shock. I met a girl who had come to the US as a child, she got caught by immigration when she was arrested at a protest in Texas. There's a law that if you are in jail for 3 days waiting for immigration, you are free to go, but they got her before that time expired. ICE came for her when she was only 18 but the rest of her family is still here. You wouldn't be able to tell that she's Mexican, perfect Spanish, perfect English, she still works for an American company that outsources to Mexico to this day.
I've been doing activist journalism for three years and I've met several undocumented immigrants, this one guy, the sweetest guy I know, became an undocumented immigrant because it was the safest way for him to come here, but now he can't leave the country even if he wants to. At least he's happy here. It usually takes six months of processing in order for a person from Mexico to come to the states, even to visit, because the government is so against anyone coming here, but for us we just need our passports because the Mexican government benefits from American tourism.