I'm not sure I understand you. Who is this "we" that can already afford to provide healthcare for the planet?

If you mean all the taxpayers in the world can afford to pay for all the health care of all the people in the world to a high standard, that just isn't true. Canada is a highly developed country with lots of resources to devote to modern health care, but much of the world is not like that. The need for health care FAR outstrips the supply. Even in Canada.

Second, we in Canada don't have any control over the health care policies of the rest of the world. If you are just musing about how the whole world should come together and prioritize medicine instead of bombs, well, sure, I guess most everyone would agree with that. But that's like wishing for world peace. It's not a realistic health care policy for Canada. As I said, and which you pointedly did not respond to, we can't freely open our health care system to the victims of America's dysfunctional health care system, not to mention the rest of the world. Sure, it would be great if Canada could heal the world, but we can't. It isn't about "fairness", it is about our ability to maintain a functioning system in a world we don't control.

Thirdly, the argument that ending military spending would significantly improve health care is a nice idea, but it is a red herring. Canada, and most Western nations, spend less than 2% of GDP on military. Ending military spending would help a little bit, but it wouldn't "solve" the problem of funding health care.