Question

what do you understand by marches in across the fence? why do people not return from marches​

Answer 1

Answer:

it describes a war, and the soldiers dying eventually in the war thus not returning.

Explanation:

Soldiers march across the fence,

fence here is the border that seperates two countries or places.

This phrase is probably about soldiers who march to war across the border of the state or place they are protecting.

And why they don't return back is probably because the soldiers sacrifice themselves and die for their country/state/or place.