On some level I get this. As a person living in Toronto I have to say, people of different ethnic backgrounds can feel extremely separated from each other in this city at times, and a lot of minority groups tend to just stick together. I've encountered more people in this city who don't speak a national language (English or French) than any other city on earth. I also can't tell you how many times I encountered students who barely understand English throughout university at UofT. It's quite common here.
On one hand, it's awesome to walk home from work every day and hear seven or eight different languages being spoken. And as a whole I love how diverse this city is. On the otherhand, it can feel strangely segregated by racial background and language at times in a way that other cities don't, because there seems to be less incentive or necessity to fully integrate.
Now, all that said, this is much more of a Toronto and Vancouver thing than a Canada as a whole thing. I've also lived in the prairies and in Northern Ontario and while things feel much less segregated there, it's also significantly less diverse.
So, I don't know. I don't even know if this is really a problem at the end if the day, but I do recognize what the underlying point being made here is; At least for Toronto it feels like a lot of people from other countries move here and don't integrate much. Part of this makes for a culturally diverse, unique, and interesting city but it also creates some challenges. It's not wrong to point out that it's a thing, though. It's definitely a thing in certain parts of Canada.