Not sure how states taxing more don't harm their own citizens. If I make $100, with 30% federal tax, then I keep $70. If my state raises their tax from 0% to 20

Not sure how states taxing more don't harm their own citizens. If I make $100, with 30% federal tax, then I keep $70. If my state raises their tax from 0% to 20%, then I pay $20 to the state, deduct that from my $100 to get $80, and pay $30 on that which is $24. So I keep $56.