I'm very torn when it comes to Social Security.
On one hand, I strongly believe that people should watch out for their own best interests and we should be able to put that 15% of our salary towards our own retirement and whatever optional disability insurance polices we want. Hell, if I could invest that 15% in bonds or even the cash funds in my portfolio, as well as buy every optional AFLAC policy, I would still be better off than what Social Security would give me.
One of my biggest gripes with SS is that those who are getting ready to retire lived their lives in an incredibly prosperous period of American history, one that in all likelihood will never come back. They also grew up in a period where a university education was nearly free (paid for by higher taxes). But, when they took over the reigns of government, they gutted education, cut their own taxes, and left us with a pile of debt. Yet, somehow the Baby Boomers as a whole weren't able to save enough for retirement, even though they lived through an era huge economic growth and low taxes... I do not feel that this generation was a responsible steward to the American economy or government.
On the other hand, I know that there are many Americans who will not look out for their own best interests (ie, sub-prime mortgages, 25 year olds going w/out health insurance when they could get an HSA/HDHP for $30/month, 40 year olds w/no retirement savings...), and I also realize shit does happen. I just don't want to live in a country where a disability would guarantee a life of poverty or have the elderly living on the street or dying of starvation.
Years ago when I used to do consulting work all over the place, I can vividly remember the elderly and disabled (the blind, amputees, retarded, massive tumors...) begging in front of churches when I worked in Romania. I realize it's an extreme example but I wouldn't want anything resembling that in the USA, even if it meant my portfolio would be 2x as big.