Yes but what about if you didn't realise that the uniformed thugs with Swastikas and torches were Nazis?
Who amongst us hasn't inadvertently found themselves marching alongside people espousing a morally repugnant cause who hid it except for wearing uniforms and shouting Nazi slogans and antisemitic chants?
Happened to me just a week ago! At first I thought that they we just an unusually militant group of adult scout leaders displaying ancient Indian symbols. It took me an hour of marching before I realized that the arms on the Swastika were in the wrong direction, and that what they were shouting was not a pro forestry chant of, "Till the Yews."
It could happen to anyone!