...his response was that I was being a smartass and I should listen to him.
It’s a shame that there are so-called “instructors” around like this, even if they are a tiny minority. Being unable to explain *why* a particular course of action is desirable and then criticising the student for asking is not a good trait for a teacher.
As I suggested in another thread, the response to these types of scenarios that appears to work best is to nod, pretend to make a note of it somewhere, then move on. Afterwards you can ask someone else that you respect to give you an answer/explanation.
I think the logic used to raise the gear is difficult to disagree with in this situation. Why would you want to leave it down and invalidate the figures in the QRH by doing so? Especially when terrain constrained. It doesn’t say to put the speedbrakes away either, should you be using them, but it makes a lot of sense...