It was a "burp", which all economies must do on occasion. Then Hoover made it worse by skyrocketing interest rates, which is the last thing you should do.
If he would have dropped rates and let the thing play out, it would have been similar to what we're experiencing now, minus the huge real estate problem that is hanging over us. But he didn't.
FDR then entended the problem by running up the federal deficit and implementing anti-competition and pro labor policies.
In an article in the August issue of the Journal of Political Economy, Ohanian and Cole blame specific anti-competition and pro-labor measures that Roosevelt promoted and signed into law June 16, 1933.
"President Roosevelt believed that excessive competition was responsible for the Depression by reducing prices and wages, and by extension reducing employment and demand for goods and services," said Cole, also a UCLA professor of economics. "So he came up with a recovery package that would be unimaginable today, allowing businesses in every industry to collude without the threat of antitrust prosecution and workers to demand salaries about 25 percent above where they ought to have been, given market forces. The economy was poised for a beautiful recovery, but that recovery was stalled by these misguided policies."