Well, I understand he didn't knew about the Keynesian macroeconomic framework, or was understandably suspicious of it's validity, as new as it was. Microeconomic theory just couldn't model an event such as the Great Depression, at the time. And even FDR, who had the correct framework, had a very unlikely event happen to the world that relieved the economic pressure of the depression. Wouldn't find blame on him for that.

Cause and effect are difficult to figure out, though we have the benefit of lots of hindsight. When you get into a problem so crazy and horrible, you sometimes have to experiment a bit to figure out how to fix things (aka "doing something"), and some of these experiments will invariably go backwards. Hoover's problem was probably he underestimated and misidentified the causes of the crash. Roosevelt experimented a lot also, and had just as many failures as successes, but he was like General Grant during the Civil War who wasn't afraid to loose troops in order to win.

You are aware he was only in office for a few months before the stock market crashed ? If you think it was his fault then I don't think I can convince you otherwise, however If you also feel that the problems we had in the late 20's could be fixed in a few years then also good luck with that. There is a reason why it took decades for the stock market to rebound after the crash and a World War to kick industrial America back into gear.