When voters say they are for mass deportation they are typically thinking of criminals and recent border crossers.
They are strongly opposed to deporting say DACA recipients and those with Temporary Protected Status (JD Vance wants to deport DACA recipients and those with Temporary Protected Status).
The best persuasion on this point might be to educate people about Trump and Vance wanting to deport all these groups of immigrants. And not just those with criminal records.