The post to which you reply was not talking about celebratory gunfire, as you seem to be. (i.e. randomly shooting into the air.) Arizona, for example, has a law against that known as Shannon's Law. However, I was unable to find a specific law against celebratory gunfire here in Virginia. The fact is, few states have laws against it. Generally, shooting randomly into the air, will get you charged with negligent discharge of a firearm, as it should. But, no, " Shooting bullets into the air," is not illegal in most states.
Aimed fire into the air, however, is another matter. exhibition shooters have been know to do this quite often. To my knowledge, there is not a single law against this anywhere in the US where shooting is otherwise permitted, and the exhibition is conducted with appropriate due diligence.
I once had to put a 30-35 degree angle on a shot when I was trying to shoot steel plates at 200 yards with a handgun. It was interesting to watch the math of parabolic motion play out in real life. It was also completely safe given the conditions.
I think, perhaps, you need to check your "facts" a little more closely.