Maybe so for some of us, but maybe not for a lot of others.
While individuals are forced to contribute, so are their employers.
That doubles the contribution for each employee.

Many of us are self-employed so it all comes out of our pockets, but most people aren't.

Back in the mid 1990's I was a wage slave for a company that had a very nice 401K program and they matched the first 6% that I contributed at 100%. I was disciplined enough to put 15% of my salary into that 401K. I would have rather had the money that my employer (and I) were contributing to Social Security to contribute to my 401K.

Of course, from 1999 until 2013, when I was president of Tightline Computers, it was even worse because, as you rightly say, our company was paying both halves of the tax.