Best thing I've read on PPRuNe for ages, Tabs. Succinct, intelligent, passionate and thought provoking.
I've always thought that we should aspire to being a multi-ethnic but mono-cultural society, assimilated as much as integrated. The only place where we might disagree is that my 'single culture' would not be fixed, and would be adaptable enough to incorporate and reflect the best of the cultures of those we assimilate, while retaining certain core values. Perhaps you feel the same, perhaps not.
But the point that we need to stick to our values in the face of attack is spot on. They must not steamroller us into Gitmos or H-blocks, we must remain what we are, a civilised, liberal, tolerant and humane democracy.