I haven't read it either, and won't like to. After his arrogant/weird responses, I'm sure it's pure intellectual bullshit. I don't know what his exact motive was, but he sure seems to enjoy the storms he's caused. I just dislike people like that.
That's not a fair comparison. I skimmed through the manifesto and followed the Damore case close enough to reach that strong opinion (I didn't just wrap myself in Guardianista commentary). After that, and watching his reactions, I just don't have the time nor care to study his manifesto line by line. Would you, if you find a person that you just cannot respect, and have many more to do and think about?