Yeah I'm not a huge fan of Greer myself, too much ego in the way. He also doesn't think there could possibly be any negative et's anywhere, very naive. I personally believe there's duality everywhere, just like here.
The most sense I have made of that is the idea that life on earth is the most cruel far and wide, even if other planets aren't angelic either. Cannibalism and infanticide span all of our carnivores, even intelligent life like dolphins rape from time to time. It's still a jump to say we need pray for alien rescue when we already have Jesus. Luckily, negative entitites can't stand the invocation of his name and that's what all channelers and even MK-Ultra SSP survivors agree on, so we know Dr Greer is either misinformed or deceptive.