That's the DHS authorization. It deals with immigration issues as a part of its investigations (for all federal agencies). But immigration action is not its primary role. They won't come looking for you because you broke immigration laws. But they will enforce them if it's found that you broke immigration laws while investigating something unrelated.
Not only is that whole different set of claims from "The FBI does not deal with immigration action," but the new set of claims are also incorrect, which you can see from the links I've already provided.
That's moving the goalposts. You initially stated that they do not deal with immigration action. Now it's that immigration action is not its primary role. Those are mutually exclusive arguments.
