Well, it's complicated, as you can quickly tell by skimming https://goo.gl/s1dLVw Technically, it's not ADA; its focus is on the federal workplace and procurement of services. I suspect that SAS and Strata have sizable government portfolios.
RStudio in that space would be defined as a "Software Tool," like IDEs specifically called out in the rulemaking. What that specifically means in any given case requires a lawyer with either the expertise or willing to acquire the expertise to determine how it applies in a particular situation. Me, I'm neither -- just experienced enough to know to run away from an area so outside my previous experience.
I haven't seen any similar statement on the RStudio website to the detailed list that Strata publishes -- https://goo.gl/Qc1MJ2
As RStudio's business picks up government contracts, I'm sure we'll see something similar.
In education, the onus for 508 compliance is highly context-dependent and situated with the educational institutions and instructors -- not software or textbooks. Individual student disabilities are very specific circumstances, and require attention case-by-case.
I teach RStudio and Tidyverse-based data science and visualizations at a public university and find them to be fantastic tools to tailor-make solutions for students with special circumstances (e.g. color-blindness, trouble with animations, etc.).