You clearly don't understand how probabilities work.
If one million people have DGU's every year that means that over a 10 year period, you'd have 10 million people who have had a DGU.
Which means if I interact with 100 people, three of them would have DGU's.
I go back to the gun violence thing. Only about 45,000 a year die from gun violence. (And yes, that include suicides, which are definitely violent). So in my life, I know of three people who died of gun violence, one of them my next door neighbor.
So even with that MUCH MUCH lower number, I know of cases where it happened.
But yet in the thousands of coworkers, neighbors, customers, vendors, I have encountered in my years on Planet Earth, I have met all of ZERO people who have ever had to chase off a bad guy with a gun. Why? Because it almost never happens.