Assimilation is a dirty word in Canada thanks to Quebec nationalism. French Canadians have always resisted being assimilated by the English so in Canada, we don't presume to assimilate anyone. The US has a so-called "melting pot" in which people of all different backgrounds are assimilated or "melted down" into a new form called Americans. In Canada, the model is that of a mosaic in which each person is an individual tile in a larger whole. Viewed at a distance you see Canada and up close you see the individual differences of each person or tile in the mosaic.
The US likes to think of itself as a more homogenous nation than it really is whereas in Canada we accept the fact that we are a pluralistic society. Conservatives on both sides of the border long for a country that resembles a 1950's TV show: almost exclusively white, almost exclusively Christian, and almost exclusively conservative in thought, word and deed.