I don't know what you're getting at with "most of them have nothing else to compare it with". Are you suggesting that Canadians are ignorant of other countries health care systems? Certainly not of America's - many Canadians go to the States to vacation or have relatives there and have first or second-hand experience with it. Also the whole world got to watch the insane debate over ACA.
Objectively, the health care outcomes aren't any better in the States than in Canada, despite the fact that it's essentially twice as expensive once you add in their insurance premiums.