Because turning the Canadian military into a serious organization will inevitably result into the question: Why?
To defend NATO: you want thousands of us to die in Russia?
To defend democracy: you want thousands of us to die in Iran/Syria/Iraq/Afghanistan?
To defend our territory: The biggest threat to the Canadian Internal Waters is the US where they don't recognize it
To defend our livelihood: Thousands to die over 25% tariffs, Slava NAFTA.
Canada is not like France where occasionally they can wiggle free and waste time and money on something like Mali, foreign policy is always at the behest of something else. Why die fighting for a decision someone makes in Washington DC?