He wasn't silenced in any way. His message reached way more people than he probably ever imagined.
I didn't say anything about literally preventing someone from expressing their views. There were lots of views expressed that equated to saying it was wrong to even try to discuss certain matters.
And let's not forget that he was fired, and many people were approving of that. That's creating, and celebrating, an environment where you should be afraid to express unpopular opinions
However, the main criticism I've seen directed towards the author of the manifesto, is that he contributes to creating a toxic work environment where women feel less welcome, which makes it hard to keep him employed in a company that wants women to feel welcome in engineering. Also that he doesn't understand the need for diversity in modern companies, that he doesn't understand the need for empathy and interpersonal skills in engineering, and that he's wrong about many of his assertions about gender differences (many gender differences are the result of cultural bias, for example).
> I didn't say anything about literally preventing someone from expressing their views.
You said:
> many people's first instinct, when faced with views they strongly disagree with, is to try and suppress those views and the person speaking them
The views weren't suppressed, they were spread, and then criticised. No doubt there are people who want to silence people they disagree with; that is nothing new unfortunately.
Whether his firing was justified or not depends primarily on whether this manifesto indeed contributed to a toxic work environment where women feel less welcome. Many people think it did. And if it did, then it's kinda hard to Google to keep him employed.
That's really the core issue here: is his manifesto intolerant of women in engineering, and does it contribute to intolerance of women in engineering? There's a vital difference between merely expressing an unpopular opinion, and expressing intolerance towards your coworkers. He's not merely supporting an unpopular sports club or liking unpopular music, he is talking about his coworkers. And that changes everything.
I didn't say they were suppressed. I said "try and suppress". Big difference. Also, what you say is equating "suppress" with "silence". They're not the same thing. I have read literally hundreds of comments, across HN and other forums, where people have made comments designed to suppress views they don't like (I've already given examples of the kinds of things I'm talking about, so won't repeat them here). Lots have literally said that people should not be allowed or should be punished for daring to even talk about such topics.
> Also that he doesn't understand the need for diversity in modern companies
If you've been reading these threads on HN, you'd know that many people would dispute that. Lots of people have argued that the memo is pro-diversity.