The core argument is not built on BS because Canada's primary source of raw steel is not Canada. Thus it is entirely possible that Canada is supplied by the Chinese who produce half the world's raw steel, and that America's spat with the Chinese over their steel is of huge significance to Canada and America's steel trade.
But no, we should rather believe that Canada is getting upset over their steel industry, which is less than 1% of the global market, as if the World's 10th largest economy by GDP would actually notice if their puny steel market went under.