I'd say that the Ayn Rand Institute is making an argument against a straw man. They frame the debate between and "Advanced Industrialized" culture, versus a "primitive Tribal" one, and its not that simple. I don't believe that "Multiculturism" necessarily is defined as being the belief that all cultures are equal, and that is the straw man. All cultures are of some value, some less and some more, depending on what you happen to value. I do believe however that trying to preserve a culture is a legitimate feeling to have, although to me I believe that that is on par with unnecessary paranoia. The influx of immigrants, which is what I know this about, will not destroy a "host" culture, it will only change it. The change can be good, or it can be bad, but "destroy" is too strong of a word. Yes, the original culture will remain no more, but immigrants do not have a strong enough impact to totally anihilate a culture. There is a certain amount of assimilation that immigrants have to make. Industrialzed nations don't have to worry about witch doctors and tribal mentality. There's nothing to fear.