First, this is about providing accurate close reasons for questions, that are most likely off-topic anyways.
There are only a few close reasons:
What do you think should be the close reason for any type of question to which you refer? What you are mentioning falls into the second one that covers a wide variety of off-topic questions, and the reason given the OP for that is listed in the box above the question as:
NE is a site for to ask and provide answers about professionally managed networks in a business environment. Your question falls outside the areas our community decided are on topic. Please visit the help center for more details. If you disagree with this closure, please ask on Network Engineering Meta.
I do not see where that is an inaccurate close reason.
Now, I don't quite get the policy about questions about ARQ. Homework is offtopic (so such questions are clearly out). However, design or theory of protocols used to operate a network is ontopic, and, understanding basic ARQs belong to theory of any reliable protocol operating either layer 2 or layer 4. On the other hand, since it is clearly basic building blocks theory, not protocols themeselves, redirecting such questions to e.g., Computer Science CE under tag [computer-networks] is probably a better option.
Remember:
Network Engineering Stack Exchange is for asking questions about professionally managed networks in a business environment.
ARQ and other academic protocols with no standard are off-topic because there is no real-world use in a business network.
Asking theoretical questions about protocols is for real protocols (ethernet, IP, TCP, UDP, etc.) used in a professionally managed network, but there is no standard for academic protocols, so the theory can be whatever an instructor claims, and they are certainly not used in a business network.
If you think a question should be asked on a different SE site, then you should add a comment recommending the SE site to the OP.