The argument was centered around the fact that the wealthy pay less, by percentage of income, than the less wealthy, into Social Security. The arguement for keeping this inequity in place was, "The weathy are less likely to use it, so why should they pay into it? It's punishing the sucessful."
The last part of that is simply a political statement, meant to disarm any counter argument. If you argue against it that means you are against success! But that's just a debate tactic. Granted it works against most of the public.
The real argument is flawed. There are a LOT of programs that people's taxes pay for that they see no benefit or they do not use, yet we pay those taxes. We don't get to pick and choose where our tax dollars are spent. I don't have kids, but my tax dollars help pay for schools. Do I get mad about that? No. Those dollars are worth giving up for the benefit of society. I benefit through an educated society.
Oh but I can hear you saying, "Social Security is for retirement help. The wealthy don't need that, so where is the benefit for them?"
The thing is, when we start paying our Social Security taxes, most of us don't know that we may some day be wealthy and not need them. We pay into it hoping that we'll be able to use those dollars later. That said, anyone with high school social studies should have learned that what we are putting in today is going out today, to the current retiree base. We have basically given the government the role of taking care of our seniors. Something that used to be a family task. Now most people just ship off their elderly family members to homes and let the government pay for it, via Social Security.
Sorry, went on a separate rant there. The point is that when we pay Social Security, it's not like a 401k account. That money is not ours. It's taxes, plain and simple. Those tax dollars are being used to fund any number of government programs that even the wealthy may be using.
This is also not about 'punishing' the successful. I've been successful enough with my career that I can work from home. Because of that I don't drive very much at all any more. Does that entitle me to pay less taxes because I use the road infrastructure less than everyone else? No of course not. The same goes for the wealthy.
UPDATE: Here is an interesting counter point to my argument. Not sure I completely agree, but I'm always open to listening/reading a reasonable argument.