It can be when a short description completely and accurately describes what's going on, but the person creating the comment needed to read a few books on the subject to actually understand both what's happening and why due to other issues.
EX: How does virtual memory get mapped to L1 cache?
> you must read a book if you want to understand it.
"Go read a book" is not a very constructive or helpful answer to a question that - as it turns out - could be answered with a brief comment.