[carussell]

A "Have you considered..." question asks for a "yes" or "no".

A "Why[...]" question asks for why.

Assuming that "Why didn't you just do X?" isn't really just a disingenuous way to say, "you're an idiot; do it this way instead", then you should ask for what you want and ask the why question, not the yes-or-no question. In the case that it is a disingenuous question, then that's something that's covered adequately by #5. Suggesting the avoidance of sarcasm is already broadly applicable enough to cover using questions when you really mean to make a statement. (Which is not specific to code reviews—it's as obnoxious in real life.)