Except they don’t do this?
“US. law does not require a U.S. citizen to choose between U.S. citizenship and another (foreign) nationality (or nationalities). A U.S. citizen may naturalize in a foreign state without any risk to their U.S. citizenship”
Yes, it does. You don’t lose other citizenships when you gain US citizenship.
You keep asserting otherwise, how about you back that claim up with proof?