It says more about the nature of pharmaceutical manufacturing than anything. We often need to screen for impurities, and cyanide is a pretty common one.
Cyanide is found as an impurity from both natural sources and as a byproduct during the manufacturing process, a lot like lead. So it's common enough to warrant the expense of testing
The author is asking for a button that is accessible and got a button that is accessible. The system never claims to an expert in the subject matter, and yet still gets the ball in the hole.
The author didn't ask "give me the most basic button you can that a screen reader can still access."
The tool did what we expect and gave a reasonable answer, and was able to reason about why it gave those answers when questioned.