Whilst I agree with the sentiment (unchecked immigration is a terrible idea), there's relatively little that Ivan and the others could've warned about in this specific instance because the damage had long since been done. The communities from which these riots erupted have existed for over half a century. Many of the rioters are second- or third-generation French citizens, at least in the eyes of the law.
What is there to do about them, realistically speaking?
By the way, don't fool yourself into thinking that what you're observing in some European countries now is foreign to America, because it isn't. There's little difference in quality between a French Banlieue and the gang-controlled neighbourhoods for which cities like Chicago, L.A. or Washington are known for. (In fact, even Marseille as France's most dangerous city is with a murder rate of 3.5/100,000 people many times as safe as these cities; it is safe even compared to the American average of 7.8/100,000 murders in 2020).
The issues are, indeed, remarkably similar despite the introduction of religion as a factor. I mean, you can be born in the US and live your entire life without speaking a word of English or without ever leaving your ethnic bubble. A criminal lifestyle, social welfare and self-segregation will ensure they don't have to leave the bubble. The West entire has no idea what to do with people who disrespect our values.