I like to be conservative with flagging, using it basically for situations of harm or potential harm—even very minor harm, like hurt feelings, or a user learning that bad-mouthing other users is acceptable. To my mind, the question was "rude" in the sense of cheeky, audacious, striking a tone unbecoming in one asking favors. But not "rude" in the sense of "low-key abuse." As comments threads get heated, one step before actual name-calling is often passive-agressive snippiness, and to my mind that's the kind of "rude" to flag.
We do get some guidance: The flag-vote includes the explanatory text "A reasonable person would find this content inappropriate for respectful discourse." The linked page contains lots of guidance, but never actually contains the word "rude" (!). It does expand on "abusive behavior," and expects "all users to treat one another with kindness and respect. And, supporting my "harm" idea, says "If you encounter something that you believe is harmful, please flag it."
Anyway, I was also inclined to overlook some of the tone because the question showed signs of being modified from a homework question, and some of the demanding language might have been more appropriate from a teacher to a student. And as I said in my comment, it seemed out of character for the user. Many of their prior questions have been flawed, but never decorated with emojis or quite so unhinged in style.