This is definitely an unsupported conclusion. the rise of the Nazi Party had started before 1929. Musolini was already in power in the mid 1920's. The Japanese militarists became powerful after teh Russian Japanese war of 1903. japan was already in China before the Smoot Hawley tariffs were enacted. germany had already experienced the hypeer inflation and depression that allowed teh Nazi Party to gain its electoral viictory. your teachers are attributing a causative relationship to something that pretty much happened after the conditions it is said to have caused.
but from everything that I've read, there are also real dangers to carrying protectionism too far.
I tend to agree and I really am not defending the Smoot Hawley Tariffs. They combined the extreme agriculrural tariffs of one house of Congress (I think the Senate) with the extreme manufacturing tariffs of the other House (I may have mixed up which was the House version and which was the Senate version). Now the harm they did is very much open to debate. Now Milton Friedman published a thesis that teh Smoot Hawley tariffs which were enacted in response to European tariffs caused teh Depression. Other economists have tried to link some political statements by Senate and House leaders about the future enactment of tariffs to Black Tuesday but that I do not completely buy into either. there is absoluetly no way the level of protective tariffs could be predicted months before enactment.