Thanks, I did indeed mean to be talking kingdoms, not phyla, and I've made that change in the article.

Of course, we can classify things as we like, if we're clear on our standards. And there's certainly an evolutionary, genetic basis for distinguishing between organisms, as you say. It's just that I think that that Darwinian perspective overlooks the forest for the trees, in this case. People may be animals biologically, but that would mean the biological taxonomy is quite narrow.