Yeah, I know what you are saying and I would not place 100% of the blame on speculation. However, it looks like it played a much bigger role than most claim. Take the case of wheat futures markets which saw unprecedented lack of convergence between futures and spot prices (to the point where you had major grain storage and food corporations demanding an investigation). Wheat prices also started to rise prior to corn prices and despite what some claim there was very little substitution of wheat acres for corn due to biofuels increases. The only other argument is that there were low stocks, but stock-to-use ratios were lower in 2003 without the price rise. I think many miss the fact that the increase in commodity prices, especially oil, has a double impact on Ag because of the high amount of fossil fuels used in Ag production. There is also the negative correlation between the value of the US$ and Ag commodities, which was known by investment houses that pushed Ag commodity futures as a means to hedge US$ valued assets. Unless I am missing something it looks like speculation played a pretty major role.
On a side note I also wonder why no one seems interested in the relationship between rising commodity prices- energy and food specifically- and the increased rate of mortgage failures in 2006-07. Surely increases in these two inelastic demand goods negatively affected peoples ability to pay their mortgages. In other words, it seems to me that the food and financial crises were connected.
Brad