In short, the Aerovores, as they called themselves, believed that humans could learn to acclimate (a climate?) to a diet of nothing but air. And Gene wouldn’t have cared otherwise but for the fact that they had invaded his domain with their stupid rhetoric. He had a hard enough time with putting up with the moaning of Vegans, but this was Darwin-award stupid. No one could survive on air alone. And it wasn’t with too much thought that his quip occurred to him. Right below the Aerovore’s comment:

Humans have adapted their dietts many ways over the centuries and lurned many things about nutrition and what we can consume and everything that we have learned abou tthe humans diet points the way toward a deeper understanding and love of the environment, our mother. We should not take from our mother Earth! With patence and practice it is possible to learn to subsist on only air. You will save so many souls!

He wrote:

You know what goes good with air? Bacon.

He didn’t think about it again for a while after that. And he didn’t know it, but bacon would come to haunt him.