Their marginalisation is a massive issue, but not one I would blame on or tie to immigration. I concede that the public eye has perhaps strayed from their plight to that of more recent arrivals to the UK, but again -that does not mean that immigrants or immigration are the cause or root of the UK's poor and their condition.
Are you not interested in the world and understanding the people and things around you? I know how trite that sounds but if I'm totally honest, that's about the most basic level of "valuing diversity".
Have you ever travelled outside of the US? We can stop this conversation right here if you never have and have no interest in doing so, but that would (IMO) be a pretty sad indictement on your view of the world.
It's perfectly understandle that one might prefer familliar things, but familliar things are only so by dint of er, familliarity -built up over time. Don't you get bored of them either? On the most basic level, are you never tempted to try a different beer, just to mix things up a bit (maybe the one in the odd bottle with the strange writing)?
You don't have to take "valuing diversity" to the level of anthropology (or turning the world into a cultural zoo) but, for my part I find it fascinating to understand how and why people live in differnt ways -precisely because they are and have been affected by such a range of circumstances.
Neither do I think valuing diversity is turning one's back on one's "mother culture", to drop another cliche, you appreciate things more when you come back to them. Having a strong grounding in one's own culture also helps to contextualise another -it also gives you more to share (i.e. not just the dope or LSD I'm clearly taking to get this - far out, man).
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