i would suggest that none of the people advocating for a more respectful campus would really challenge the right to express unpopular opinions in an academic setting.

I don't think any of us can know for certain how these particular students would feel about specifically academic speech. That said, I simply can't buy the idea that none of the people who push more a "more respectful" campus wouldn't apply the same attitudes to academic speech. After, there's a long history of student activists trying to prevent controversial speakers from speaking on campus (I've had two speakers whose events have been shut down by protesters in my academic career, at two different universities), and there are certainly cases of students reacting badly to controversial material in the classroom (in the only case I've dealt with, it was a conservative student who was offended I taught Marx, but I had the full support of the administration). When we have reports of student groups starting up kitty petting stations for students who are traumatized by controversial speakers being present somewhere on campus, there's a problem. And even at Yale, just in the last few days, there's been a case of protesters spitting on people who attended a talk in which the speaker made a comparison that some people took offense at. So no, I'm not buying the idea that nobody wants to stifle academic speech. Again, I can't speak with certainty about any particular protester, but I think I'm well justified to be suspicious that at least some of them might carry those attitudes into the classroom (even if, thankfully, they usually won't be backed up by the administration).

And in any case, one thing people seem to forget is that the protests weren't just about the content of the email, but about Christakis's refusal to condemn his wife's email. It's admittedly sometimes hard to determine which particular issue the protesters are arguing with him about at any given time; and it's possible that even those embroiled in the arguments weren't all on the same page all the time.

the broader issue of whether universities are more progressive or conservative environments really has nothing much to do with 'free speech' at all

Yes, it absolutely does. It's like you keep ignoring everything I'm writing about the ideal of free speech: the free exchange of ideas in the search for knowledge. If the free exchange of ideas is being hindered because people with certain perspectives don't feel safe expressing those perspectives, then the ideal of free speech in an academic setting is being undermined.

'free speech' does not mean, okay let's give equal stage time to creationists and evolutionary scientists

I said nothing about giving "equal stage" to different opinions. A person who is advocating something like creationism probably not expect to make it very far as a biology professor, and that most biologists won't consider it worthwhile to engage their work. But there's a difference between doing work that fails to impress one's colleagues and doing work that gets one labeled as the Enemy, as someone who is immoral and cannot be tolerated. A charge of racism is fundamentally different in this case because the one accused of racism isn't just worried that his or her work will fail to impress and merit a promotion, but that it will amount to social suicide and the death of their moral reputation. And if we cannot articulate what constitutes racist speech apart from causing subjective offense to someone somewhere, then anyone who has a slightly different perspective on race than the dominant one is going to be compelled to keep their mouth shut and avoid the risk. You can't "avoid the emotive connections of racism," because it's emotional, moral investment that people have in the issue that makes it particularly volatile. You can be a creationist and a good, trustworthy person who is otherwise welcome in the community. You can't be a racist and a good, trustworthy person who is otherwise welcome in the community. And that's the crux of the issue.

personally i don't think it's a coincidence that the more intellectual an organisation is the more progressive it tends to be.

This kind of sentiment--which draws a rather clear correlation between liberalism and intelligence--is exactly why many people who deviate from the liberal consensus are afraid to be vocal about it, and may simply choose not to pursue an academic career in the first place. When you're surrounded by people who give the impression that disagreement entails less intelligence, then the natural desire to want to be accepted by your peers means you're going to want to stay in the closet.

So no, it isn't a coincidence. It's not a coincidence because it's damned hard to hold an extreme minority position, especially an extreme minority position when exploring ideas is literally the main part your job description, and especially when people are morally and emotionally invested in the issue.

Your statement is offensive, by the way. But the fact that you made it does reinforce the suspicion of many non-liberals that the "safe space" crowd only cares about not offending certain people, while others are fair game. I'm not sure if that's the impression you want to give, but it's certainly how it comes across.