I started smoking cigarette when I was young but quit nicotine and changed to cannabinoids only later. I have been a smoker for decades. I guess this is why I do not have any coughing reaction or any discomfort after smoking green.
It is true that smoking itself is a harmful activity. However even such harmful activity could be beneficial to human as any medicine as a double-edged sword.
In fact, coughing is also a normal action to kick out bad things from our body. Of course, you need to be careful not to aim such bad things toward innocent others!