Theres your answer why we dont have it. we have no infantry that attacks tanks, like what these candles were designed to do. and tanks already come with smoke shots (which arent used very effectively),.
You didn't read what he read very well, or at least failed to comprehend it.
Info from Wiki:
The Nahverteidigungswaffe was a smoke candle discharger for German panzers which could also be used as a close defense weapon to combat close assaulting infantry.
I emphasized the part you failed to comprehend in Butcher's original post. As you can see, it wasn't primarily a close defense system, it could be used as such but it's primary purpose was to fire off smoke candles.
because there is nothing in the game to warrent them being used in the historical way they were.
without any assaulting infantry, there is no historical role for these tubes to fill.
Having them on German tanks would be historically accurate, as well as their use in game.
The Wurfbecher system that was previously used was mounted on the outside of the turret and when struck by small arms fire (or any other fire for that matter I would guess), crews could sometimes become incapacitated from their own smoke candles. This led to the Nahverteidigungswaffe being developed to help protect the tank crews.
This is what the Wurfbecher system looked like.

The Nahverteidigungswaffe was moved inside of the turret and protected the crews from being incapacitated as was possible with the old Wurfbecher system.

Since the primary use was to provide a smoke screen to obscure the tank, it is something that should be added to the German tanks that had it (first appeared in 1944). Even on the German tanks that didn't have it, they should have the old Wurfbecher system to provide them with the ability to obscure themselves with a smoke screen.
ack-ack