I have to take issue with your claim about ported guns not being louder.

Being the head firearms instructor at the PD I work for, I had the opportunity to test fire a PC Shield in 9mm that had been forfeitted to the PD by the court following a court case. When shooting, I wear a good pair of 3M muffs. Never had an issue with noise with pistols, rifles, shotguns or anything else when wearing these muffs, including an M2 machine gun at an MG shoot at one time.

After shooting a magazine through the PC Shield, my ears were ringing, even through the muffs. I have a standard Shield in 9mm and never had the issue. The muzzle blast was quite a bit louder out of the PC Shield and was a lot sharper. Maybe it was just me, but you can't make the blanket statement that noise increases from porting is BS, because for me with this gun, it wasn't. Maybe it's not an issue for most people, but it was for me, and I can't believe that I'm alone.

Porting can also be bad when shooting from retention. If you can remember to cant the top of the gun out away from your body when firing, not a big deal. If you forget to cant the gun outward, the blast from the ports can and has caused injury. The vast majority of the time, all it does is cause a sharp blast of gas and, aside from maybe blackening your clothes, no big deal. But it can cause injury, usually by blasting out unburned powder. Most people don't train in shooting from retention, so most don't know about the issue, but it is real. Because of this, my PD won't allow ported guns for duty use.