You didn't say "foreign born", you said "enormous diversity."

Those are very different concepts.

"Unlike so many other countries, we integrate and assimilate our immigrants"

What does 'diverse' mean to you? Since I don't think it means what you think it means. Assimilation is a process which reduces diversity.

Also, in that list the US is indeed #1 ... in the total number of immigrants. If you re-sort by "Immigrants as percentage of national population" then it's:

    UAE - 83.7% (but I don't include guest workers)
    Saudi Arabia - 31.4%
    Australia - 27.7%
    Canada - 20.7 %
    United States - 14.3%

By all metrics, it seems that Canada has both a more diverse culture than the US and a higher percentage of immigrants than the US. That's the country you should be praising, not the US.

The main factor in all of these numbers is that the US has a high population. Once you switch to per-capita, it drops in the ranks.

Congratulations, there's a lot of people living in the US.