Well, what do you mean by foolish? The socialist economists are anything but stupid. People tend to dismiss socialism as pure stupidity, but that’s only because they are ignorant of the opposing argument (or partially ignorant). Many socialists have put forth clover and seemingly plausible arguments in favor of interventionism (they’re still incorrect, but clever nonetheless). Stiglitz, for example, makes an argument where he attempts to show that high interest rates actually lead to malinvestments (moral hazard and adverse selection) as opposed to low interest rates.
Also, you have to realize that the counter-arguments were given to you. Brilliant men refuted socialist fallacies, and there is a historical record available to us. These arguments may seem obvious now, but they weren’t at first. Those “obvious” refutations were economic breakthroughs, revolutions. I think you’re taking too much for granted.
Nevertheless. Austria, in the 20s, faced extreme depression, mass inflation, the people were yearning for socialism, and they had a socialist political leader. Mises overcame all of this with pure logic, and appeals only to science.