I don't think Canadian ovens feature the temperature scale because they are sold in the US. The SKUs are likely to be different and changing the display is easy. Consider cars which are also very similar. I assume Canadian cars feature speedometers in KPH and external thermometers in Celsius. I am curious what units your engine coolant temp uses though!
Canada is a commonwealth country and the commonwealth didn't begin converting to the metric system in earnest until the 1970s. This is over 100 years later than the rest of the world. Canada paused metrication in 1988. Cooking is likely to have been one of the last things to change because it is so common.
Pre-metrication Canada used the Imperial system and the US used the US Customary system. This means the definition of units like the gallon was inconsistent. Units in Canada seem to be influenced more by the commonwealth than they are by their southern neighbor.
A lot of things in Canada are imperial because of the influence of the US. The Ontario building code says when framing a house, wooden studs need to be on 406.4mm centers. That sounds like a really weird number, until you realize it’s actually 16”. It has to be metric, but it also has to evenly divide 4 feet, because drywall here is 4 feet wide so we can import/export from/to the US.
Does Mexico have similar mixed units for cross border trade? Seems more likely to me Canadian sizes are the way they are because of the Imperial system and commonwealth history.
The US never used the Imperial system so even when both countries used gallons they were different sizes.