All it takes is one.
One piece of burnt popcorn ruins the smell of a whole bag.
One racist can ruin the perception on an entire group.
One bigot can ruin the opportunity for an entire company.
Don't judge an entire group by one A**hole. Sifting through takes practice and patience that not everyone has, nor should they always need to.
Perception is everything, are there traits/aspects of your life that are overshadowing the talent you have to offer? What is your burnt popcorn, and what is it costing you?