It *is* a bit condescending... but that's not against the rules.

It comes as both  part of an answer to the question, and in answer to a question from somebody starting out with Bash scripting. Suggesting a learner do some book learning is not a bad suggestion.

It could be *improved* with relevant links out to (I would assume) TLDP, or some other page that further explains the answer. But cutting the suggestion out completely that out doesn't improve the answer.

> What should be the correct course of action here?

Vote, improve or ignore. There's nothing that *needs* to be done with it.