The difference is that the loopholes rich people use generally actually exist, while the "loopholes" advertised by sovereign citizens are obvious nonsense like

The difference is that the loopholes rich people use generally actually exist, while the "loopholes" advertised by sovereign citizens are obvious nonsense like "by filing the right paperwork I can make the government give me a million dollars they're keeping in a secret bank account for a government-created corporation that's named after me except with all caps".