I'm very sad to see some of the names on this list: http://www.theguardian.com/theobserver/2015/feb/14/letters-censorship My personal view is they didn't fully appreciate what they were signing. That's what I hope anyway.
First off the incident that the letter is framed around is not even an example of "no platforming" as the gig in question was not going to be picketed (unless it was to be spontaneous) and the reasons for the cancelation were not down to a no platform policy at all. Which is not to say lots of media and individuals haven't framed it that way. I've read all sides and also saw the dispute that started it all happening live on twitter and these are the two sources I think get closest to the reality of it:
But regardless of the accuracy of the incident in question what about "no platforming" in general? That is definitely something that happens. It is something the letter tacitly endorses for people whose views they (and I) object to: ie fascists. But that they object to when applied to people they agree with. And some of those people hold views I often find just as objectionable as fascists. I defend the right of people to express their objectionable views. If they face state censorship, violence or imprisonment I would hold my nose and support them. But that isn't the same as denying them a platform.
Not that I would personally advocate no platforming any of the individuals in question. I think a more useful political strategy is to picket and protest their events rather than to give the speakers the martyrdom they find in being "denied" a platform. I always think of Nick Griffin proudly wearing his gag.
Fear of free speech being exercised in the form of protest is one of the elements that led to the incident that started this. The right of people to protest is a very important free speech. We should support the rights of people we don't agree with to protest.
The right to be given a platform however is not really to do with free speech. Someone being no platformed by a group or institution is not them being prevented from speaking. They are being prevented from speaking at a specific place because that group don't want them there. Whether you agree with that groups decision or not has nothing to do with it. No one has the automatic right to speak in universities. Who gets to speak in universities is of course an incredibly complex and often problematic matrix of politics, power and privilege. There are lots of criticisms to be made of how that works and strategies that we can take to deal with it. But framing it around free speech is just disingenuous.
When the people we are claiming are "silenced" are journalists and authors with national and international reputations, books, columns and the like, it becomes an even flimsier argument.
Another problem with the letter is it is specifically partisan but pretends not to be. It frames the arguments that surround this conflict as being anti-feminists verses feminists. It is not. It is two different feminisms attacking each other. (And even that description is reductive.) One of those feminisms has a wider voice and more access to platforms and they are the people who wrote this letter (which got published in a national newspaper.)
I wouldn't say all the signatories of this letter are aware of this. I doubt the nuance of the debates was communicated to them. Free Speech is a very important thing. And so it can be used to scare people. Ironically into things that limit free speech such as anti-terrorism laws, anti-protest laws, actual censorship and the like. In this case it can be used to say both that people from marginalised groups shouldn't be listened to because they are bullies (I'd suggest you will find bullying on both sides of this conflict) and also that people who already have a platform should be allowed to speak from every platform. That isn't free speech it is power consolidating it's position.
And finally the idea of what violence is is again a contested and complicated issue. You can argue transphobic or whorephobic academia or comedy leads to actual violence just as you can argue it for white supremacist or misogynist academia or comedy. Plus some people who get no platformed have done worse than just using language in a violent way, some support conversion therapy, police violence and the doxxing of individuals.
As I have said I support free speech and am sad about all the attacks on it we have going on at the moment. But no platforming isn't one of those attacks.
There are many acts I wouldn't book to perform at my nights because I find them objectionable. That is technically no platforming them. Should I be expected to book anyone who wants a platform?
I'm not being given a platform to speak at every university in the country. This is clearly an attack on free speech.