This is disappointing from DHH. He tends to carry a lot of criticism online, and based on my exposure to his ideas in long form media, I tend to agree with him more than not. However, in his linked post on this issue, it strikes me as being written by someone whose understanding is largely based emotions evoked by provocative news headlines. But, I'm going to refrain from attempting to psychoanalyse an individual who I know very little about (further than the previous sentence).

OP's post, I think, correctly points out that DHH appears to believe that British == White. Wish he'd be clear on this point, as he's often claimed and indeed has been in the past regarding other issues. Dancing around it shows a lack of respect for the audience and/or a sign of weak conviction.

If you believe in something strongly enough to want to have an impact on its discourse, why not be clear about it? Here's an example of a clear statement regarding this particular issue: "I believe that our country ought to aim for demographics where 80% of the people on our streets look like us [whatever that happens to be]". What's so difficult about that? A clear demand/objective easier to vote on/measure/debate....everyone knows that, then why do the proponents of such ideas always dance around being specific?