I agree it's a subjective issue -- personally I find it intuitive to keep all the directions consistent between the mouse arrows, keyboard, and joystick: pull back (down) = increase pitch, push forward (up) = decrease pitch. TBH it would feel backwards to me to have the AP mouse arrows behave one way but the keyboard and joystick the reverse way.
However, I do understand the OP's point, so what I'll do for the next XR patch releases is add a config file preference setting to invert the AP mouse arrow behaviors if the user sets that.