But as you said, sp "...there's a great unifying 'Americanism' which everyone buys into."
Here in the UK there is no such unifying principle. Quite the reverse, in fact. Incomers have been actively encouraged to continue their lives as if they were still resident in their country of origin. Many of them feel no allegiance to the country in which they (and often their parents) were born and in which they will almost certainly spend all their lives. Furthermore, I don't believe that in the US (or indeed many European countries) that the native language can be largely ignored as an irrelevance by large numbers of the population. Here in the UK official papers are translated into a myriad of foreign languages. Interpretors are provided at taxpayer expense for people who cannot speak English to engage with many different bodies. This simply doesn’t happen on such a wide scale elsewhere.
No, multiculturalism cannot be enforced. But it should not even be encouraged. It is divisive and does nothing to promote the well being of the nation and the evidence of that creates many of the problems we see today. That’s what Mr Honeyford was talking about all those years ago and I would suggest that far from being vilified, his views should have been embraced and discussed.