If the government contributed a dime, you know where they got it. So I am not too concerned if they didn't kick into the kitty.
I question the assertion you are getting back only what you put in. If you apply interest at T-bill rates, which is what you earn on a government backed "risk free" investment, there is a good chance you will receive more than you contributed, if you can make it past 78 years of age or so. Most estimations show that even with market returns, you will receive more than you kicked in, if you can make it to around 78 years.
Some not-quite-neutral reading: Beat SS Returns
So can a Ponzie scheme be considered a socialist enterprise?
There is no doubt its a type of Ponzi scheme once the government declined to contribute their part and stole from the system more than once.
The chickens are coming home to roost.
Neither party will allow SS to fail. It will go on with government money.
THAT is socialism.