I just started reading the Horus Heresy novels. Starting with TALES OF HERESY. Thought that might be a good way to ease into what's coming.
And in that book I read the short story "The Last Church". And you know what?
The Emperor of Mankind really is a scumbag and the Heresy is more his fault than I can possibly describe.
Based on that story and what little I know of the Horus Heresy, I'm beginning to think that the whole thing was a natural reaction to the Emperor's supreme act of egotism... if not outright divine intervention. Humans will NEVER be able to let go of their natural drive to look for something beyond themselves. Whether that's in religion or enlightenment of some other form. For one man, even one as allegedly "ascended" as the Emperor, to declare that to be obsolete and unneeded...
Yeah, it was a disaster waiting to happen. And now the Imperium is getting its just deserts for the Emperor's folly.
I'm now thinking of making my own chapter of Space Marines that are secretly Jewish, like the hidden Jews in the final Dune novel that Frank Herbert wrote. Just my own way of saying "up yours" to the Emperor and that no man can ever completely destroy faith, while also acknowledging that *maybe* he's realized the mistake he's made and is trying to own up to it.
(Well, make them either Jewish or Amish )