Let others discuss whether it was legal, or smart, for Google to fire an engineer for voicing uncomfortable views on gender diversity. It's perhaps more important that the valid points in James Damore's manifesto aren't drowned out by the chorus of condemnation.
"Feminism has made great progress in freeing women from the female gender role, but men are still very much tied to the male gender role," Damore, a former senior developer at Google, wrote in the memo that made him the darling of conservative websites and cost him his job. "If we, as a society, allow men to be more 'feminine,' then the gender gap will shrink, although probably because men will leave tech and leadership for traditionally feminine roles."
Damore used that point to argue that there are nondiscriminatory ways to bridge the gender gap, which may not all benefit Google with its workaholic culture. He was half right. Making sure men take on the "female" roles that have caused the gender pay gap removes unfair competition in "traditionally male" jobs and narrows the pay gap without any dangerous economic effects.