Well I guess different people have different opinions about what is "relevant" and a "fad".
I haven't seen any Perl in production use in a number of years - although I'm sure it exists, for me and my career it's way past being "relevant". I was using it 20 years ago...
Scala is highly relevant, it's a fantastic language which I've been using professionally for over 2 years to great effect. I've built infrastructures serving millions of requests per second using it - and I'm not alone - Scala is widely used at Twitter, LinkedIn, Netflix, FourSquare, AirBnB, Apple, ... the list goes on.
Java is widely used, of course, but it's kind of dull at this point. Relevant but there's not much new to talk about at a conference.
Rust is .. interesting. I don't think it's ready for production yet, but it has some really interesting ideas, which even if they don't make it in the form of Rust could be seen in future languages. Very relevant to discuss and think about.
Go is spreading very quickly - I personally don't care for it but in my last job we had ops people who swore by it (I just swore at it). Extremely relevant right now as so many places are evaluating it, plus, obviously, the Google link.
The others - clojure, racket, & co are niche for sure. I don't think they even qualify as fads because (with the possible exception of clojure) no-one's really using them - and fad implies something is popular.
I do think they could have included F# though, that's a really interesting language that's starting to pick up steam in the commercial world. And Swift, while not that revolutionary, is bringing some new stuff to the masses and spreading very fast.