So, by that logic, you can simply go to Los Angeles and shoot illegal immigrants, since they have no legal standing and are committing a crime by being on US soil. Is that what you're saying?
I believe that would be your logic. No one was shot. They were detained.
If you are asking "So, by that logic, you can simply go to Los Angeles and DETAIN illegal immigrants, since they have no legal standing and are committing a crime by being on US soil."
The answer would be yes.
It is the State which is the plaintiff in murder trials not an individual.