Data processing benchmark but somehow R is not even mentioned?

It would be the slowest language result on the list.

Slower than Python? I seriously doubt that

Port the script to R, benchmark and report your results. Python is slow, but R is generally much slower.

I will have a look, but R has much better data structures than Python for data processing (everything is a vector in R)

EDIT: they have one script related.R in their repo, which is 3 years old, and uses jsonlite as a package which is notoriously slow. Using a package such as yyjsonr yields 10x performance, so something tells me what whoever wrote this piece of code has never heard of R before.