You should have argued it as application level based DoS, most triagers look out for keywords, the fact that the triager saw DoS, and DoS is usually out of scope which is mostly Network based DoS ie sending thus of request but in the case you just have to share a link with the victim and the user won’t be able to access other parts of the application. Back to triagers, I believe most look out for keywords without looking at the full reports cos they have more reports to attend to, that’s why it was closed as N/A