why did the west commit to multiculturalism?

[Papewaio]

So Australia which is a culturally hetrogenous population is not a happy social democracy?

Now these are only sourced from one think tank, so automatically the sample population is not great. But as these were at the top of the google search I'm sure you can find something to counter it if your premise is correct.

From the happiest countries in the world 2010:
1. Norway
2. Denmark
3. Finland
4. Australia
5. New Zealand

The World’s Most Liveable Cities Top 10 List 2011:
1 Vancouver, Canada
2 Melbourne, Australia
3 Vienna, Austria
4 Toronto, Canada
5 Calgary, Canada
6 Helsinki, Finland
7 Sydney, Australia
8 (equal) Perth, Australia
9 (equal) Adelaide, Australia
10 Auckland, New Zealand

But it kind of torpedoes the idea that one needs to have a culturally homogenous population to be happy as that is not the key.

I don't see the poor as being worse off for immigration. The uber-rich can afford a butler, its the middle class and poor who are more likely to require the help of a lower wage earner. Take call centres in Australia, they are about as diverse a group of people possible. Call centres are run by a much higher percentage of immigrants and second generation then the rest of Australia. The low cost solutions that are call centres are catering more for the middle and poor segment of the population.