SS is basically a crappy retirement plan for poor people. It's even worse for rich ones. Given that, it's irrational to call it a tax.
PS: Given the choice I would give my SS benefits if I could avoid paying SS taxes.
So the basic numbers are 70 * .14 * 1.06^40 = 56k / year in retirement but SS cap's at 1/2 that so at least 1/2 of SS is pure income redistribution for a young person making 70k.
Granted if bad things happen SS will help me or my family out, but that's the definition of welfare. And if I die before 67 I am left with nothing.
PS: SS is not just about retirement, but life and disability insurance is cheep and I still pay for it have and I have been paying for over 5 years at this point and 6% over inflation is a vary low number for 40 years.
Other arguments I've seen on that page: America is a classless society (evidence: if you look at people who are poor when they're 20, they're often much richer when they're 40). The poor are "lucky duckies" for having such low tax rates (evidence: tax share statistics which take account only of the income tax, ignoring the state, local, and payroll taxes which make up the majority of the burden for the poor). I'm sure there have been others. I don't know if these have been mainly by the editorial board themselves, or op-eds.
I have nothing particularly against market liberalists - I respect the Economist, and Reason Magazine. The WSJ just doesn't seem honest.