Because 90% of them never saw him, focusing on their kids, friends or phones.Mall full of mom's and kids shopping for back to school.
Guy walks across the parking lot .
Carrying a AK with ear protection on.
And nobody engaged him.
Because why .
Most of the people who did see him probably never put it together that he was on a "mission"
And finally, there are darn few warriors in this world who who could recognize the situation for what it was and act appropriately.