From the article:
"These numbers raise profound questions that are seldom even asked: What number of immigrants can be assimilated? What is the absorption capacity of our schools, health care system, infrastructure, and labor market? What is the effect on the environment and quality of life from significantly increasing the nation's population density?" wrote Steven Camarota, the Center's director of Research.
Profound questions seldom asked? You mean there might be a problem here? Overwhelming immigration might not be a good idea? Sometimes, people who have tried to ask these questions have been called racist and bigoted and haters. All not true, but that is the sad state of our ability to have meaningful discussion about difficult problems.