Because there are still huge numbers of people alive today that grew up and went to school before Canada officially switched to metric. Don’t forget that we’re trapped by the Americans. Where I live I can literally see the individual buildings in the city across the river which is upstate New York. There are several radio stations along the border that do their weather reports in both °C and °F. Personally… I’m 6ft tall, 235Lbs, every liquid is in litres and temperatures are in Celsius. My oven has both F and C. Driving in Canada is usually measured in time when speaking to people. I know that Toronto is about 4hrs away on a good day and it can be 7hrs on a bad day in the winter. Don’t get me started on accidents or construction. I have no idea how far it is in KM. I’m guessing maybe 400km since the speed limit is 100kph and it takes 4hrs to get there.
FWIW, I’m 45yrs old. So I’m really trapped in between the two systems. I prefer metric but my parents and many coworkers were born and raised pre-metrification.