Clearly Nazi technology was superior to even what we have 70 years later. ~s
Even by game standards this argument doesn't make sense.
Firing through a building means going through at least 2 and probably many more walls (of various construction) and would still have affected projectile speed, trajectory and probably stability. A tumbling projectile will not have the same effect, which is pretty much the whole purpose of rifling or fin-stabilization.
The argument for a bunker busting projectile from a 152 makes a bit more sense, but probably still shouldn't be in a game where shot blockers are so important.
Actually there are historical reports of German heavy TDs firing thru walls. The high speed projectiles where hardly affected from few bricks and could actually destroy the average allied tank with easy.