Good pros and cons of Go language. There is some information around why Go and not say C++/Java/Ruby etc. The statement "I see Rails as the emperor with no clothes on" seems to be made in haste, since Rails is awesome for basic forms based apps.
Disclaimer: I am a Rails developer. My views are therefore biased.
It's also likely that TFA's author was frustrated with performance under load, where Ruby (and Python) generally do not shine.
When this thing is a substantial increase in speed, sometimes you are totally f*ed, since to get it you need to toss away a lot of the detritus. For an ORM you can gradually phase away parts of it, but for a web framework generally you can't architect away the box into which your app is placed.
I'm unaware of any RoR that has successfully scaled, except by removing Ruby (Twitter). Github is probably the largest existing Rails app (at least that I use), and there are Unicorns aplenty (the new fail whale), or weird caching issues that seem to arise regularly.
Ruby is slower and more resource intensive than some alternatives, but clearly it's possible to scale to large numbers of users and developers with RoR:
That's not to say that choosing an alternative or rewriting a particular service or website in something simpler/faster/cheaper isn't sometimes a better option, but I don't think you can claim convincingly that Rails is impossible to scale.
As always, right tool for the job.