A lot of the slides are about why he wouldn't use Perl, why he wouldn't use Java, and the like. His whole argument is that there's no other language in the efficient / nice to program quadrant. To make that kind of argument you have to cover all the options, and at least place those languages somewhere on the diagram (or acknowledge why you aren't).
> You can certainly go ahead and ask them "Why not use OCaml, F#, Haskell or Scala", or you can use FP to make a better project in this field to show people FP is indeed much better fit.
Well, that's what I do. But Go seems to get a disproportionate amount of coverage on HN, particularly compared with what people I've met in real life are using. (at least here in London. Maybe it's much more popular in SV?)