I agree with your analysis, but the fact that soc. sec. taxes don't generate a credit or deduction hardly means they're taxed twice.
On the other hand, if Babs and the other airheads/meatheads want to eliminate taxes paid on soc. sec. benefits, hey I'm all for cutting taxes.
Yes, you are taxed on it twice -- paying federal and state income taxes on your Social Security contributions (if they are not considered a deduction) is paying tax on it once; then you pay tax on it again when you start collecting SS. That's twice.