The people that protest privatization don't understand investing at all.
Actually I don't think you understand anything about a very important part of investing and saving: human emotion. Now it
shouldn't be a as much of a part of these as it is but to ignore it is to be completely dishonest about the environment in which you invest and save
While proposals vary most contain two provisions: Self directed investing and program directed investing towards a ROI goal which may even be guaranteed
I am completely against privatizing because of this. SS is a safety net and as such it should be managed more carefully than a great many people are willing to treat it. If you believe in the Efficient Market then you already know that higher returns are gained for the taking of risk. I prefer my safety net to have minimal risk
For the self directed portion all you need to do is look at stories like GT and Sapphire glass to see that greed, ignorance and herd mentality\group think can destroy people's entire retirement savings over the weekend. There are literally millions of Americans who bought at the top in 2007, sold at the bottom in 2008\09 and didn't buy back in until 2013+. Its one of the big reasons middle class wealth has lagged.
Now you can say that they should have known better and are stupid for putting all their eggs in a basket like that or panicking and pulling their money out at the bottom and I agree. However - this is a safety net and if enough people lose their net it
will become your problem
Programs with guaranteed returns also have a bit of a problem when managed by politicians and popular opinion. Pensions and their creeping upwards return promises provide numerous examples of failure, not to mention many notable cases of fraud costing taxpayers hundreds of millions
And, of course, there is the part where it only takes one or two very easy changes to SS to fix the entire system....