Their arguments are bullshit. You deport them when you find them . That will be at schools, hospitals, and traffic stops.
Construction sites...
Sanctuary cities, welfare offices, etc.
I’d look at the polling places. And under the Mexican Flags.
No need to go looking for them.
During traffic stops, arrests, and when they attempt to use benefits designed for for US citizens, hospitals, etc they can be arrested and deported. In fact you process and get rid of half the illegals within 5 years or so. Incrementally, 1 at a time, thousands per month get caught up and booted.