Can you cite the sources you researched? I’ve known people from all over the world and none of them found that to be true: the American healthcare system was commented on in disbelief over both the cost and difficulty of getting treatment compared to where they had previously lived.
The first result when you Google Canada's healthcare waiting lists: https://pmc.ncbi.nlm.nih.gov/articles/PMC7292524/
Yes it is. The system has some very deep issues due to government involvement/meddling with both healthcare and insurance, but at least you can still receive life saving treatment in a timely manner.
They can be in disbelief all the want, but when people in countries with socialized healthcare get cancer or other life threatening medical conditions they come to the US and a private healthcare to get treated.