Gizmodo actually edited the "manifesto" (it's a loving memo you dips calm down) to not include any of the graphs, sources or fancy editing. Here's the ACTUAL unedited memo:
https://assets.documentcloud.org/documents/3914586/Googles-Ideological-Echo-Chamber.pdf
All of his claims are backed by science and notable sources like The Righteous Mind by Jonathan Haidt. This kid has a Master of Science from Harvard and a BS from the University of Illinois, both degrees SPECIFICALLY in Biology. He knows what the forget he's talking about. Better yet, he was a leftist who had suggested a better way of getting women into tech than using diversity quotas and discriminatory hiring. To say that this guy was a troll who pulled things out of his ass to piss some people off is wrong on all levels.
The best part is that everything he said got proven true not even a day after he was fired. He says that Google has a problem with different opinions, and they fire him, saying that they don't like his opinions. He says women on average tend to be more emotional and on average take more sick days, and a substantial group of women got so offended that they collectively took a sick day. Things couldn't get any better for this guy.
biology =/= sociology or psychology tho, which is what is relevant in terms of his memo's topic.
did you read the article on medium posted a few times in this topic? the third point in it, which is about how the memo would create a hostile working environment, is honestly a pretty valid point, and is strong enough grounds to fire the dude. having this memo internally distributed and talked about would divide the workplace into people who support him and people who dont support him, and would cause workplace politics that would actively get in the way of doing their job.
eg: imagine if you found out your coworker was leisuresuit/kimon, and vice versa. if both of you were in the same room, wouldnt it be far harder to focus on doing your work? or at least far easier to have simple conversations flare up into resentment/workplace conflict?
now imagine if leisuresuit, red spy, seventh, and corderlain were around too. its pretty easy to see why they needed to fire him immediately