As I have already pointed out, balancing one solid object upon another solid object has nothing whatsoever to do with Aerodynamics, which deals with the behaviour of solid objects in a gaseous medium, most specifically Earth's atmosphere.
As
you have pointed out? I am afraid that the great Herr Professeur Poppy Leghume pointing out anything about "rokitts" does not alter the facts one iota!
How did the Saturn Vs, Space Shuttles and even Space-X get off the ground. You might not believe that they got into orbit or had any thrust in a vacuum,
but, they certainly did get off the ground and ended up pretty high!Whatever
the great Herr Professeur Poppy Leghume might think, balancing a rocket on its tail is a very similar control problem to balancing a broomstick!
You are I suppose an expert on closed loop control systems too! I used to find them a bit hard, but of course no problem for
the great Herr Professeur Poppy Leghume.
Smaller rockets can have a launching rail to keep them straight till they achieve enough velocity for aerodynamic stability.
But large rockets accelerate too slowly for this to be practical, so they need an active balance control system or they can go unstable, and we seen that happen often enough.
I'm sure you'll be enthralled with all the information on gimballed rockets etc in
How Do Rockets Maintain Stability At Liftoff?