exactly -they told you right -
in vertical attitude - it is not loaded -at all - until you start to rotate it with the ailerons - so IF you plane weighs 40 lbs for example - in a exactly vertical attitude --it is not loaded with 40 lbs (lift required to fly level )
this is why it is so easy to over yaw or over pitch in verticals - you are not overcoming the loads from gravity.
just a momentary flick of elevator or rudder will set up the AOA necessary to stall a panel.
You are working against airloads tho -