Perhaps if the issue was raised as a pull request with the desired changes to the Readme, rather than just raising the issue as a general whine.
The whine itself stinks of someone not having gone through the source to see if the product really does what they want it to do. It reeks of "hey this looks like what I want YOINK! " , implementing it in their code, and discovering afterwards that some Things are missing. Then getting pissed off at the producer of the product, rather than at themselves for their oversight/laziness.
I've been using open source for 20 years and I don't think I've ever had to do that. Sometimes I have to fix bugs in a library or ditch it because it's a piece of crap. However you generally shouldn't have to read the source code to see what it actually does. If so, that's just laziness on the part of the author (and it's wasting everyone's time).
The whine itself stinks of someone not having gone through the source to see if the product really does what they want it to do. It reeks of "hey this looks like what I want YOINK! " , implementing it in their code, and discovering afterwards that some Things are missing. Then getting pissed off at the producer of the product, rather than at themselves for their oversight/laziness.