I assume by putting the flags in the shape of a cross, the placers of the memorial are comforting themselves with the idea that the fallen soldiers' souls have gone on to Heaven. Something to the effect of: Yes, it is tragic that they have died, but they are in a better place.
I suppose that you would prefer that they cover the flags in dirt and have the worms devour it, since that is what you imagine is actually happening to the soldiers' body, and that we should not kid ourselves with the state of their soul, or lack thereof.
Of all the things to be "annoyed" about.... You must make your parents very proud, kid.