How do details such as "stone or metal,” "many pigeons,” "towers,” and "wild cats that roam the god-roads” establish setting?

By giving the image in your mind of what the setting will look like with those key items in it.

Explanation:

The answer is because of semantic fields.

Explanation:

A semantic field can be understood as a group of words that are related among them. Putting all the words in the same text (stone or metal, many pigeons, towers, and wild cats that...) setting is established because all of these words together can create the picture of somebody in a room or hallway in a castle, or at least, in a similar environment. It has to be mentioned that the connection between "stone or metal" and "pigeon" is not very close, but if the other quoted words are added, we can talk about a landscape that belongs to a very particular context.

the speech this question is referring to is president kennedy's special message to the congress on urgent national needs, may 25, 1961

kennedy responds in a very direct and concrete way to those thinking that communism is a positive system:

"yet their aggression is more often concealed than open. they have fired no missiles; and their troops are seldom seen. they send arms, agitators, aid, technicians and propaganda to every troubled area. but where fighting is required, it is usually done by others--by guerrillas striking at night, by assassins striking alone--assassins who have taken the lives of four thousand civil officers in the last twelve months in vietnam alone--by subversives and saboteurs and insurrectionists, who in some cases control whole areas inside of independent nations." (kennedy)

president kennedy presents communism as cowardly, as a hidden and treacherous weapon that strikes from the shadows like thieves, he represents the system as not even being capable of showing and open and overt attack or confrontation. to finish up the response, he expresses that the system attacks even a country's idependence and freedom.