Part of this weird mass delusion is the belief that "protectionism failed" or "the welfare state failed" ; you will frequently see these assertions in supposedly factual news articles. Papers like the NYT which will parrot ridiculous government press releases without question will also say things "free markets have clearly proven themselves" or "nobody wants a return to a welfare state, that model has clearly failed".
Huh, really? I find that interpretation highly dubious; certainly not something that can be dropped as an aside as if it's incontrovertible. During the golden age of America (roughly 1950-70) we were highly protectionistic and we had our most generous welfare state. So, where was the failure? I'm sure the popular memory is somewhat fixated on the bad times of the 70's-80's that were blamed on corrupt unions and inefficient protected businesses and supposedly saved by Reagan/Thatcher free marketism. But there are numerous complicating factors that make that interpretation questionable at best.
The only indisputable success of the free market era was the dot com boom, but that would probably have happened anyway in a more controlled market system (and we may have avoided some major crashes due to excessive speculation and capital liquidity, such as the southeast asian crash and the south american crash).
In the mean time, highly protectionist / socialist states have been doing very well (eg. most of the scandanavian and german speaking states). I don't mean to imply that they are a good model for us to copy, but if you're just looking at world evidence for certain economic/political schemes, it seems there's more pro-socialist examples than there are good "free market" examples.
I believe that part of the problem is the mathematical appeal of free markets in theory. You can set up these toy problems with idealized conditions, and talk about what creates the "global optimum" for all.
There's nothing wrong with playing with toy models, except that people then think that it applies to the real world. A serious economist would be able to list the various ways that the idealized models don't match reality, but then you start drawing yield curves and run simulations and cook up formulas and it all looks so nice that by the time you get to the end you forget that it doesn't actually connect to reality.