I think there can be an interesting discussion on the benefits of integration vs. diversity, even if I personally think diversity is something that is good. Integration has good sides and bad sides; the good being the focus of the original article, the bad being horrendous xenophobia and terrible treatment of those who don't integrate. Shutting discussion down as if things don't have multiple sides isn't very liberal, in my opinion, even if I personally disagree with the focus of said discussion.

Culture isn't race... Are there actual comments from "race realists" somwhere I'm missing, or are you raging against something that doesn't exist?

No I haven't seen the zenophobia. Granted I only live here so maybe it is more obvious from SF?