They thought he was a bad president. They blamed him for the bad economy. There is a brand of vacuum cleaners called hoover. You could remember that by saying he was a "Sucky" President.
The bad sentiments are also seen in that there were Hoovervilles, which were groups of homeless people that were often large and called themselves Hoovervilles because of their distrust and dislike of Hoover, who they blamed for the economy.
