That makes me wonder about two things:
1. Is Mixtent wrong?
2. Do companies really see Ruby on a resume and say "nope! next?"
It is easy to shoot these superficial programmers down, even from a cursory browse of a resume.
It's not that Ruby signals that you're a superficial programmer; it's that there are fewer superficial Python devs, and more superficial Ruby devs.
For the most part, your choices of programming language are a terrible way to differentiate or market yourself. You are far better off being clever about picking your application domain.
I don't like Python; I'm a Ruby developer (actually, I don't know why I stopped calling myself a C dev). But I'll freely admit: most Python programmers know Python because they spend their real day job programming.
Given that another big influence was ability to be a team-player then I can see how ruby guys are perceived lower on the list.
Hiring decisions aren't typically made in the same way. If you have a Rails app, you need a Ruby developer. Granted, anyone can learn Rails, but I've worked with really talented people who were in the process of learning the Rails framework, and it's not something I'd like to pay for again.
Their raw data may or may not be accurate, it's impossible to say because they fail to present the raw data or detail their methodology.
Their interpretation of the results is at best simplistic and incomplete, and their post title is absolutely wrong.