It seems that it is you who is coming to the table with the pre-conceived notion that the program is an absolute good and that the letter is an absolute bad.
I read the letter. It has some very good points - many of which feminists have been pointing out for ages, to the surprise of nobody who's actually been listening to feminists. It also has some terrible points, and uses a severe misunderstanding of gender to attack women who work for or intend to work for Google. The decent points it does make are mostly an aside to the main point, which is that the author has a very strong belief that diversity programs are inherently bad and that women are biologically weak engineers.