The takeaway seems to be all available data suggests black and Asian ethnicities are over represented, even though a plurality are white. But then says there are data collection issues. Well yeah, but the data we do have says one thing and there’s no obvious reason given to disbelieve it. Unless we assume that all the cases where offender ethnicity wasn’t recorded were white people, but generally you assume missing data acts the same as data you’ve seen unless you’ve a good reason to think otherwise.
When you’ve got a situation where there’s a feeling of political correctness coming before justice, I’m not sure it’s wise to keep plying the same rhetorical games. Honesty and openness needed here, not concern that the facts make a group look bad. If there is an issue in some communities we need to know so we can design interventions that work for that community.