I believe they have not thought things through properly. He had a good point, not to mention a sense of humour, but I disagree. It's not even that common. If you count either species or organisms you find hermaphroditism, bisexuality, asexual reproduction and plenty of instances of homosexualtiy, even among species that mate for life, such as swans. Creativity is not just about making babies, remember.
Polarity works as a mental tool.
For many purposes you have to transcend such primitive notions. I find this debate offensive. I see no reason to make this assumption. This varies from group to group. With so many Pagan religions it is not possible to say that all Pagans celebrate the same festivals.