Canada better pay attention to the one factor they probably already know about but they're just discounting. They live right next door to the United States of America. China's halfway around the world. They need to pay attention to that fact.
We're wildly aware. Currently 80+% of our trade is with the good old USA. We're basically an economic colony. But when the ambassador to Canada and Trump himself note that they don't need Canada (both statements happened in the last 2 weeks) we don't really have a choice but to attempt to diversify. We don't want to do it, we were reasonably happy with the existing arrangement, but it's not up to us to decide what the US does. It's up to us to decide what we do.