Not everyone thinks this, but I know an extreme right-winger who thinks this. He is also a conspiracy theorist who thinks non-white people are out to get white people so, yeah, odd.
Not every immigrant is illegal or bad. I know a girl who didn’t speak English for 3 years when her family legally immigrated, so of course she’s been told this.
A lot of people are influenced by alt-right news (Fox News, Newsmax, OAN) who keep repeating the false claim that undocumented immigrants are mostly gangsters and violent criminals. In truth, undocumented immigrants are way less likely to commit a violent crime than an average American citizen.
Trump said, regarding the first deportation flight:
Yet none of those deportees had any criminal conviction in either country (according to Newsweek, a slightly-right news source).
remember: oligarchs are the real criminal enemy, not your fellow 99.9%