It’s not the short-term effect that is damaging, it’s teh long-term effect.
https://www.history.com/news/trade-war-great-depression-trump-smoot-hawley
https://fee.org/articles/the-smoot-hawley-tariff-and-the-great-depression/
https://www.daveramsey.com/blog/what-are-tariffs
https://www.washingtontimes.com/news/2017/jan/5/the-problem-with-tariffs/
http://www.businessinsider.com/trump-trade-war-tariffs-study-on-economic-impact-lost-jobs-2018-4
https://www.investopedia.com/articles/economics/08/tariff-trade-barrier-basics.asp
https://www.thoughtco.com/the-economic-effect-of-tariffs-1146368
Only 4.3% of the economy was internationally traded at the time and Smoot-Hawley only affected about 1/3 of that (agricultural imports mostly) so you are arguing that a slight rise in tariffs affecting 1% of the rural economy was a major factor? Ridiculous.
Smoot-Hawley had, if anything, a slight stimulative effect on American farming and no major impact on anything else. International trade dropped because overall demand dropped following the crash.
The globalists themselves know they are lying when they trot that one out.