As a Canadian, I do see reports of police violence in Canada, and I imagine I'm largely seeing the same stuff you are, so you've also likely seen some. With that said, police violence per interaction is a pretty low % everywhere (to be clear, it should be 0), but its like 10x higher in the US than other comparable countries, and the US has a huge population. Because of a combination of those factors I wouldn't be shocked if like 90-95% of police violence happening in English speaking countries is happening in the US.