It says more about American business ethics.  Remember, the US claims our tax inputs into R&D are a government subsidy to Bombardier.  But Boeing is divided into commercial and military divisions.  The military division is hugely subsidised by the pentagon; they make impressive technological gains.  Those gains in knowledge and technology are subsequently embedded into the commercial division's products.  But there is no direct $$ link between the tax money and the commercial division.  So the US claims Canada's tax inputs are a subsidy and that the US doesn't give Boeing subsidies, which is patently untrue.