When you've just been fired and seemingly the entire world is against you, you're going to be drawn to the only group that provides you support (in his case the alt-right). It's just human nature. It is a serious mistake to deduce the motives for his original memo from this.

Indeed, I thought it quite telling that Damore's subreddit, that he actively moderates, is full of posts and comments hating on women.

And also that he's embraced becoming something of a folk hero for alt-right dullards.