Homosexual behavior is "bad" because it is described in scripture as an abomination. The "badness" is God's judgment not ours and does not depend on any sort of human ratiocination. To say it is "unnatural" has no bearing on the moral judgment, although anal sex for example is "unnatural" in the sense that it clearly violates the natural ecology of the body.
Animals and human beings can perform any number of more or less equivalent behaviors, including attacking and killing members of their own species. But this fact contributes nothing to the debate about any given behavior. We do not set animals up as moral arbiters.
For Schori to suggest otherwise "because animals do it" is more or less a reflection of what happens when a squid expert tries to play anthropologist when she is supposed to be playing theologian but has not the education or the temperament for it.
"To say it is "unnatural" has no bearing on the moral judgment"
"We do not set animals up as moral arbiters."
I agree with both those statements. I won't bother to argue theology, as I'm not much of a believer.