It's interesting to me that kangaroo meat is banned in California but it's legal in Australia.

Speaking of, Kangatarianism is a "recent practice of following a diet that cuts out meat except kangaroo on environmental and ethical grounds."

https://en.wikipedia.org/wiki/Kangaroo_meat#Kangatarianism

So why is it ethical to eat kangaroos, but not cows?

According to the Wikipedia entry, unlike cows, "Australian kangaroos live natural lives, eat organic food, and are killed humanely."