https://en.wikipedia.org/wiki/List_of_countries_by_intentional_homicide_rate indicates that Canada’s intentional homicide rate is considerably lower than that of the US. However, it is hyperbole to say that the US is “one of the most violent on the planet if not the most violent (aside from an active war zone)”. It is true, however, that the US has a significantly higher rate than other rich countries in general. But many poor and middle income countries have much higher rates than the US.
Within the US, Massachusetts has a relatively low intentional homicide rate, so it may look as if much of the rest of the US is a high crime zone if one lives in Massachusetts.