Was it 9/11? The attacking of our nation by a group of Muslim extremists, perhaps, stirred still waters that ran deep. The instinct to be wary/suspicious/hostile toward people who are perceived as being "different" may be lodged deeply in the DNA/human culture- stemming all the way back to when "those strange people from across the river" might come over and steal the tribe's winter food stores.
I'm not saying it's right. I'd like everyone to use their cerebellum to reason, and to learn more evolved social behavior. Sadly, that seems a tall order for some...