I agree that personhood is a broader concept than civility, but it's not so broad that it encompasses wild animals. Higher mammals have minds and societies but that doesn't make them people. We treat pets as part of our family, so maybe we think of them as people in some extended sense. But notice that that's only because we've trained them and thus stripped them of wildness (i.e. of animality, which is opposed to personhood).

The question is whether personhood ends up inevitably in a civilized state, so that our obsession with domesticating nature is something like our destiny or ultimate purpose.