You can't hand out Burger King coupons inside a McDonald's.
You can't paint your company's logo on another company's front door.
But they are doing it to the USCIS's website... And making a profit from it.

USCIS's website is their front door, their billboard, their marketing tool, their catalog.
It's their virtual office where they provide their products and services.
It's their brand, their face, their property.

USCIS should consider (and view through their own testing) the possibilities of who else may buy ad space that triggers off of their domain name and their site's content.

US Taxpayers fund the USCIS.GOV website.
Why does the FTC allow companies to advertise and profit from it?

Further resources.