They’re doing what they should have been doing all along: enforcing the visa rules. The system is being gamed so they have to crack down. There are around 10-15 million illegal immigrants in the US, not including mass visa fraud. It cannot continue.
"Give me your tired, your poor,
Your huddled masses yearning to breathe free,
The wretched refuse of your teeming shore.
Send these, the homeless, tempest-tost to me,
I lift my lamp beside the golden door!"
A poem on a plaque on a foreign statue, written 107 years after the formation of the United States is neither legally binding nor central to what the US is. And the poem doesn’t endorse visa scammers.
It's not legally binding, but it is central to what the US is and has been. That's why they put the poem there, and that's why Americans welcomed the gift and erected the statue, and that's why it has been considered to be one of our most cherished symbols ever since.