They basically advocate using R. I think it depends what they mean by "data science" and if the person will be doing just data science. If that's the case then R may be better. As in their whole career is going to built on that domain. But let's say they are on a general computer science track, now they'll probably benefit from learning Python more than R, simply because they can use it for other purposes.

> Either way, I’ll not discuss it further here. I’ll also not consider proprietary languages such as Matlab or Mathematica, or fairly obscure languages lacking a wide ecosystem of useful packages, such as Octave.

I feel, to most programming folks R is in the same category. R is to them what Octave is to the author. R is nice nice, but do they really want to learn a "niche" language, even if it has better some features than Python? Is holding a whole new paradigm, syntax, library ecosystem in your head worth it?