45 posts is statistically insignificant. Of course you will never have an issue as long as the grip safety is depressed. The problem happens when you are unable to depress the grip safety. Shooting at the range is not the same as being in a life or death street fight.
In the real world you may find yourself with no other choice but to fire from some very unorthodox positions you will never practice at a range because they would be too dangerous. How are you going to use your gun with your face in the dirt with an attacker on your back beating you in the head. You don't practice for that at the range.
Quite a few guns are deployed when the victim is on the ground with an attacker on top pinning them to the ground. You may already be wounded with a gun covered in blood, mud, or sweat and with broken fingers. You could be moments from passing out and need to fire the gun with some other finger with no possibility of a "proper" grip.
1911's have failed to fire under the same type of situations because the gun owners could not operate the grip safety. There is a reason 1911 grip safeties were often taped down or disabled by lawmen years ago. The XD safety is even more likely to fail because of its design, but it has not been around long enough for many, if any documented cases. It is also almost never used by professionals who are likely to be in this situation.
Yea, I know I just described an extreme situation that may never happen to you. But this type of scenario is more likely to happen than any accidental discharge being prevented by a grip safety. I still say grip safety's are more likely to prevent the gun from firing when you need it to fire, than when you don't want it to fire.
The idea of grip safeties have been around for a while. It was stuck on the 1911 because of governmental bureaucracy, not because John Browning felt it was needed. It is on the XD to sell guns to people afraid of Glocks. Over the last 100+ years no other major gun maker has felt it was needed.