Within about 20 years, the US won't even be a majority white nation. Pretending Canada is more diverse than that, is ridiculous. That Canada is somehow a super diverse nation, is a pretend claim that is unsupported by the actual demographic facts.
Why don't more poor black people immigrate into Canada from cities like Detroit, Chicago or New York? Surely their lives would be considerably improved given Canada's superior safety net, healthcare system, etc. - and Canada has good wages and a healthy unemployment rate. It's simple, they're not allowed to. Canada's immigration system excludes the possibility that most people with lower skill & education backgrounds can ever get in.
If Canada were actually pro-diversity, they'd liberalize their immigration policies and let in a large amount of immigration from Latin America (after all, the vast majority of the Americas is hispanic), such that Canada's hispanic percentage closes the gap with the US over the next 20-30 years. They're never going to allow it.