I think you're not getting his key point, or you are but you're being coy about it. He did say skin colour, in the form of "native Brits". How do you know that? Because of the article he linked, defining the terms he was using. The article is called "Ethnic groups in London", not "Cultural groups in London". He quotes statistics about "native Brits" that match the article's demographics for "White British". There is zero ambiguity here.

If I say "I love a [sweet treat](wikipedia.org/wiki/ice_cream)! It's so refreshingly cold on a nice hot day", there's just no intellectually honest way to claim maybe I meant apple pie. Do you understand? He's not talking about Russian immigrants because they're white. He is talking about Pakistani immigrants because they're brown. He's literally telling you what he means and you're choosing to ignore it. Why?

Perhaps there are, in fact, reasons to not say skin colour even when that's what you mean.

Hilariously he's talking about Londinium, a city founded and administrated by non native non British people as part of a foreign beachhead of control by a non British empire. "Native Britains" were excluded as residents or in tiny numbers for four centuries.

London has always been a hive of culture, he's just pining for the nostalgic times he wore onions on his belt and was blind to the depth of culture in London.

There have been Russians in London since before the USSR, not that DHH would have noticed unless they spoke given so few of those Russian were Asiatic or from the steppes.

His point was that he has now finally noticed changes and that he's had his eyes opened by the likes of Stephen Christopher Yaxley-Lennon, Andrew McMaster, Paul Harris, Wayne King, and Tommy Robinson.