Multiculturalism only works in nations that have no pre-established cultural identity.
In Canada's case, we didn't start with that unified idea that the southern colonies had.
We started as a fragmented people, the french had the east, the british had the inland, the natives had the central area, and then there was whatever the fuck happened out west. Everyone retained their own cultures, and only unified AFTER the fact to become a nation known as Canada.
Therefore no pre-established culture existed, we were a checkerboard of all cultures from conception, no identity to defend.
The US did not really attempt to allow co-existence between the colonials and the natives, and outside of the spanish to the south, other cultures really didn't exist to be adopted into the identity of the nation.
As such, the US formed a unified cultural identity, something to form a standard on by which foreign influence could be easily identified as in contrast.
When something "unamerican" enters the US, it clashes with the pre-established cultural identity.
When something new enters Canada, it becomes just another pin drop amongst the deafening background noise of cultural differences. Nobody cares, it means nothing more than your hair colour to us.
The only thing that can really be established as Canadian cultural identity is our secular values and strong held belief in civilization. No one religious belief is above the secular values of the western world, and the only thing that can be identified as foreign is therefore anything that rejects western civilized secular living.
This is why we're inevitably going to clash with modern Islam. Modern Islam is rejecting western secular civilized life, and is going to be quickly identified as Canadians as the first truly "foreign" entity to us.
However, all the other cultures seem to have no issue amalgamating into secular western civilized life, and as such, we don't clash with them, they're just like the rest of us.