They can't see the devil even when he's everywhere in plain sight.

a) Devil is in the detail/detaillier - "cut into pieces"

b) Sight implies within whole (perceivable)...what other partials are showing (suggested) tempts one to ignore whole.

c) Plain (inception towards death) sight (life)...what others are suggesting towards ones sight tempts one to hold onto it (information) while ignoring that ones perception within all perceivable moves (inspiration) and therefore cannot be held onto.

mental gymnastics, newspeak in their heads

Aka suggested information upheld willingly within ones mind/memory.

Nature doesn't speak...it moves sound. Those within shape spoken words to distract from moving sound.