No Safe Spaces Much as I delight in a post in which Stephen Hawking is compared, unfavorably, with one of the creators of The Man Show, I think that it must be acknowledged that questions regarding why the universe exists and why we exist are more likely to be answered by science than philosophy, if what's sought is an explanation. But it doesn't follow that philosophy is dead, although if philosophy is defined as being confined to answering those questions I doubt it has anything to contribute beyond what philosophers have already toyed with in the past. I'm inclined to think philosophy involves more that Hawking gives it credit for.
Also, Hawking by stating philosophy is dead isn't claiming that philosophy or philosophers must be silenced. All in all, using his example to introduce or as representative of what's referred to in the trailer is confusing at best.
As to the trailer. For a lawyer, the right to free speech applies only where government or its representatives seek to restrict it. The right itself is subject to restriction in the law; it isn't absolute. The right to free speech being referred to in the trailer, and by others, therefore, isn't a legal right. It merely happens there are people who think people should be free to say anything they want, and generally they claim that this should be the case because, e.g., we otherwise would never learn and people shouldn't stop other people from thinking or speaking, and that we should have diversity in thought and speech. J.S. Mill used to speak of the good results of having a "marketplace of ideas" or words to that effect, where views compete and bad ones fall to the side through the workings of a kind of invisible hand of communication.
It's difficult, however, to claim that people should be allowed to communicate hateful, bigoted, violence-inducing claims and ideas, for example promoting genocide or slavery or inferiority of races and such things. Mill notwithstanding, I wonder if anyone really does claim this. Instead, they claim "free speech" is being restricted whenever it's maintained that people shouldn't be allowed to do so.
The fact is that some speech is inappropriate. But the determination whether it is or not isn't a simple thing, and such devices as the creation of "safe spaces" treats it as a simple thing.