No. That property only holds for stuff that have "penetrating" shells. e.g.,:
- Jagdtiger piercing rounds
- B4 direct shot
- etc
In order to fire through stuff, you also need to be able to ignore shotblockers. Smoke only acts as a shotblocker. Ergo, smoke is treated in the same way as buildings; it's ignored
So if I'm understanding this right, smoke acts as a shotblocker in that units do not attack through it. But it doesn't actually block shots, which is why Attack Ground is an effective counter.
Possible fix, maybe: Increase aim time x1000 while in smoke, so it does not fire. Attack ground would need to use a separate weapon then in order to still be usable.
Things to watch out for: Being abandoned while in Smoke might leave it permanently crippled, as CoH2 likes to make temporary modifiers permanent when a unit is abandoned. Also double-tapping by using attack ground immediately after a normal shot is fired.