Touching the plate and cup, whether you eat and drink or refrain, is intended by the WT to allow you to express your hope - either going to heaven or staying on earth.
And yet they emphasize that only a relative few are going to heaven. And most of those have already died. So anyone who eats/drinks of the emblems becomes the object of others immediate judgment as to whether such a thing is really possible for that person.
There are many ironies in this WT ceremony:
1. The only ones who partake without question are the leaders, the governing body at headquarters. To question their partaking is to question their authority. Everyone else who partakes is somebody that 'believes' they are going to heaven. But as far as the leadership is concerned, that remains to be seen.
2. JWs go to great lengths to invite outsiders to "observe" the Lord's Evening Meal. Yet, as you pointed out, they take pains to make sure everyone participates by being handed the plate and cup. If you noticed after the passing of the cup and plate, the brothers who did the passing of them must sit down and have the plate and cup handed to them. This, despite the fact that they have been handling the plate and cup as they passed it to all those in their seats. Finally, the the speaker has to be handed the cup and plate in the same ritualistic way. He is required to show where he stands on the matter.
It seems to me from points "1" and "2" that this is an exercise in establishing who the leadership is and who those being led are. You show the acceptance of your place as a follower of the GB by passing the emblems without partaking.
3. Another irony is that Jesus (and Paul) described the eating and drinking of the bread and wine as a way of 'remembering Jesus' death.' But at the Kingdom Hall, eating and drinking the bread and wine (or not doing so) is all about where you hope to go after this life.
And I agree with your point about why have non-partakers in attendance. How odd to be invited to a ceremonial meal in order to watch others partake of it. Or in many Kingdom halls, to watch nobody partake of it. What a waste of food that Jesus would never have approved of (compare John 6:12; Matthew 14:20; Mark 8:8; Luke 9:17)
Bobcat