Imagine you have a friend and hang out with him all ghe time, and everyone knows you're friends because you're always doing cool stuff together -- then suddenly his brain is compromised (by propaganda or something) and he becomes a strong Nazism supporter going so far as to claim that he secretly supported it all along!, now you're looking like a nazist yourself.

Does that mean we should have never had the concept of love and friendship and all people should be forever alone?