that is not 100 percent guaranteed. it depends how you were raised and your exposure to others. I have seen many people wave with their two middle fingers leaving the both the pinky and the index finger up in the air looking like one of your satanic hand signs. and these people might have never known about anything satanic...
One in a million.
Perhaps these people are a part of the "cult" and they were waving at you and you're a part of the cult.
Did that every cross your mind?