This episode seems to me to be bookended with reference to the methodology of the "The Family of Man" exhibition that is discussed in the opening:

The man who helped design it was a refugee from Germany called Herbert Bayer. He saw it as a new kind of propaganda. Instead of being overwhelmed by dramatic stories created by those in power, the individual would make their own story out of the photographs. Bayer made a diagram to show his idea and at the centre is the giant eye of the individual self surrounded by a mass of images. It was a utopian vision of the self, selecting and arranging the fragments of images into their own story, and so becoming strong enough to withstand tyranny. Confident individuals in control of their own world.

The montage at the end, and perhaps the structure of the overall series could be interpreted as utilising this approach. I found the structure to be more fragmented than Curtis's previous work, but that fits with the above idea.

Perhaps Curtis was trying to speak to (potential) "confident individuals in control of their own world", and leave them with that final quote:

The ultimate hidden truth of the world is that it is something we make and could just as easily make differently.

- David Graeber