You've also made the mistake of thinking that just because you've found one problem that others must not exist. We can have broken systems and problems caused by immagration.

10% ESL students in our public education system should qualify as a strain. 17% of California's prisoners being born abroad should qualify as a strain. Are these numbers not high enough for you? If not, what does too high look like to you?

Second, my main assertion is the existence of a point where immigration is problematic. Example: colonialism.

Third, as to the side conversation of whether or not America is experiencing a problematic level of immigration I've already submitted the fact that 10% of students in US public schools are ESL learners. We can add to it that 16% of California's prisoners were not born on U.S. soil and they're so overcrowded the Supreme Court ordered them to do something about it. I'm calling these things "strain". I hope we can agree that immigration plays a role in both examples.