It has not been insulated at all, there are tons of federal immigration pathways made easier for french speaking immigrants. According to this https://www.statista.com/statistics/444906/number-of-immigra..., Ontario does seem over-represented.

I'm not saying over-immigration has no downsides, clearly it did not help our overstrained system, but to say it caused it is to willfully blind ourselves to the structural issues that lead to these issues in the first place. i.e. they will never be fixed