Never did get any answers on this... My guess is because in order for a theist to answer, they would have to be truthful about their god and they just can't bring themselves to see their god as taking anything other than human form. To admit that there is a possibility of their god taking a non-human form would be to challenge the brainwashed thinking they hold. We can't have that now, can we?
Disclaimer: I am only responsible for what I say, not what you choose to understand.