However, what proportion of those who cycle badly in the USA are recent immigrants? I don't know, but I suggest that it is not greatly different from the proportion of those who cycle badly in the USA in any case. Our problem is America-wide, and throughout American society.
I probably wouldn't disagree, but I don't know the data. And we are also talking about several overlapping categories, recent immigrants, hispanic cyclists, etc. etc. so that does make the issue less clear.
However Helmet Head says that the biggest factor in determining how you are treated is your own behavior. So I would take it that when he looks at the fact that hispanic cyclists are killed out of proportion with their numbers an mileage, he would say that it is likely their behavior that caused this increase.