It's both the fact that they're going after people here legally and even U.S. citizens, and the brutality and unconstitutional nature of their tactics. They are literally going house to house kicking in doors without a warrant. They're racial profiling. The ICE agents are completely out of control as their recruitment standards are nonexistent and higher-ups are signaling that they can do literally whatever they want, including killing people, and they'll face no consequences. I don't understand how any sane person can support it, much less the "don't tread on me" crowd.

Detaining and/or deporting people here illegally to their home countries with due process: OK

Detaining, deporting, and/or killing people here illegally, legally, and U.S. citizens, without due process, to private detention camps or third countries: NOT OK