they abandon themselves to the bestial stupor which gapes at existence, and they think they have seen something.
This rather looks like an early critique of what much later Edward Said calls Orientalism. Said commented as someone born and brought up in the middle-East he couldn't see the texture of life he knew in the representations of such in art & literature; they're represented in their exoticness & foreignness as something to 'gape' at.
People commonly travel around the world to see rivers and mountains, new stars, birds of rare plumage, queerly deformed fishes, ridiculous breeds of men
This rather looks like it is. Comments like this were common enough then. Similar remarks were made by Hegel and Kant for example. One might excuse them on the basis they hardly had first hand acquaintance of these peoples themselves and were going on second or third hand reports; but on the other hand one might say, of all people, we might have expected better of them.