Remember the Pepsi commercial where they pulled a bunch of people together to sing and hold up a Pepsi?
Those people did a convincing job. They probably were swept up in the moment (plus they were paid) and perhaps believed they really would help world peace.
They were a group of strangers pretending to be something....
that is exactly what jehovahs witnesses are doing.
People are drawn in and saturated in the idea of global unity and "love" so they each assume the persona and seeing each other do it reinforces it.