That's not what we're doing here. What this article really is an examination based on a set of assumptions about how we can measure expressiveness. This is a difficult thing to measure. You could (I assume) do just as well by polling thousands of programmers and asking them in their experience, which languages are expressive. In the case of this article, the measure of expressiveness used seems to match up very well with a) common programmer experience and b) the intentions of language designers. And we're not talking about programmer experience in 2013. This split between Lisp, C, and Fortran is older than I am.
I do not see anyone offering better measures of expressiveness or suggesting counterexamples to invalidate the results. The criticism here is just "Meh, not impressed".
Vala and C# are two very similar langauges that are on polar opposite sides of the chart. Why? If I can't answer that in a convincing way, my first thought is going to be "because there is another factor involved in the rankings that wasn't accounted for."
I don't think anyone is saying it is completely uncorrelated with the real thing, sure if you split the chart in half the languages on the right will mostly really be less expressive, but this we know without having the chart anyway and the more granular results don't seem trustworthy.
I do not see anyone offering better measures of expressiveness or suggesting counterexamples to invalidate the results. The criticism here is just "Meh, not impressed".