Every anglosphere country drastically increased immigration in the mid-1960s.
And they also threw it wide open to the Third World, where previously it had been preference to White, English speaking countries.
(and abortion, and legalized homosexuals, all at the same time...)
Canada was also a massive refugee destination. More so in the 1980’s and 1990s.
I think that immigration has become so massive they just come in as immigrants now. (500.000+ in 2023. The equivalent for the USA would be 5 million)
Yes, it really was the wave of the „new left“ making itself felt.
But whose fault was it? I blame several things, among them the unprecedented prosperity of the Fifties and Sixties, but also the bad conscience of many people towards the nations of the Third world.
Some have said that this might have been the fault of the „Greatest Generation“ but maybe the „Silent Generation“ helped more. The Boomers were, I think, for the most part too young to have had much political influence before the late Sixties and Seventies.